Meat-eating by early hominids at the FLK 22Zinjanthropussite, Olduvai Gorge (Tanzania): an experimental approach using cut-mark data

The meat-eating behavior of Plio-Pleistocene hominids, responsible for the bone accumulations at the earliest archaeological sites, is still a hotly-debated issue in paleoanthropology. In particular, meat-eating and bone marrow consumption are often presented as either complementary or opposing strategies of carcass exploitation. The presence of cut marks on fossil archeofauna is a potential source of information that has not been consistently used as evidence of carcass consumption by hominids. Some authors interpret cut marks as the result of hominids manipulating meat-bearing bones, while others argue that they can also be the result of hominids extracting marginal scraps of carcass flesh that have survived carnivores’ initial consumption. In this study, a referential framework concerning the interpretation of cut marks is presented, based on a set of experiments conducted by the author. It is suggested, according to these experiments and data drawn from the FLK “Zinj” site, that hominids processed meat-bearing bones (on which flesh was abundant) rather than defleshed carcasses from felid kills.     

Testing meat-eating in early hominids: an analysis of butchery marks on defleshed carcases

The diet of early hominids responsible for the bone accumulations at Plio-Pleistocene sites is still a controversial issue. Meateating and bone marrow consumption are often presented either as complementary or as opposing strategies of carcass exploitation. The occurrence of cut marks on fossil bones at early sites is a potential source of information that has not been consistently used as evidence of what products hominids obtained from carcasses. Some authors interpret them as the result of manipulating meat-bearing bones, whereas others believe that they can also be the result of extracting marginal scraps of flesh that have survived carnivores’ initial consumption of carcasses. In this study, a referential framework concerning the latter process is presented and it is concluded, according to the data drawn from the FLK “Zinj” site and the results obtained in the experiment, that hominids processed meat-bearing bones (in which flesh was abundant) and not defleshed carcasses from felid kills. This work constitutes a reference that can also be used for later Pleistocene sites and adds a further dimension to the hunting-versus-scavenging debate.     

Taphonomic perspectives on hominid site use and foraging strategies during Bed II times at Olduvai Gorge, Tanzania

The faunal assemblages excavated by Mary Leakey in Bed II of Olduvai Gorge, Tanzania, have, like the more well-known Bed I assemblages, traditionally been interpreted as the result of hominid butchering activities in the lake margin and riverine settings of the paleo-Olduvai Basin. A reexamination of all of Leakey's Bed I sites has shown that hominids played little or no role in the formation of all but one of those faunal assemblages, a finding that prompted the reanalysis of the Bed II sites presented here. We expand upon a previous taphonomic study that provided systematic data for HWK East Levels 1–2, MNK Main, and BK. In addition to these assemblages, we provide data on HWK East Levels 3–5, FC West, TK, and SHK. Our data contradict previous interpretations of MNK Main as a hominid accumulation but uphold the contention that BK represents a primarily hominid accumulation reflecting early access to carcasses. The small and poorly preserved assemblages from FC West and TK are difficult to link unambiguously to either hominids or carnivores. Site MNK Main and HWK East Levels 3–5 appear to be death arenas where carcasses accumulated via natural deaths and/or serial predation. Site SHK is severely biased by selective retention and therefore little can be said of its formational history. Nevertheless, no hominid modifications were documented in this assemblage. Comparisons with other Olduvai sites indicate a more conspicuous hyena taphonomic signal during Bed II times than Bed I times, which appears to mirror the changing configuration of the large carnivore guild. These findings also beg the question of what activities were being carried out by hominids with the stone tools discarded at these sites. Although it seems clear that hominids were utilizing stone tools to carry out subsistence activities unrelated to carcass butchery, more excavation and techniques such as phytolith analysis should be employed to explore alternative explanations.     

New estimates of tooth mark and percussion mark frequencies at the FLK Zinj site: the carnivore-hominid-carnivore hypothesis falsified

Traditional interpretations of hominid carcass acquisition strategies revolve around the debate over whether early hominids hunted or scavenged. A popular version of the scavenging scenario is the carnivore-hominid-carnivore hypothesis, which argues that hominids acquired animal resources primarily through passive opportunistic scavenging from felid-defleshed carcasses. Its main empirical support comes from the analysis of tooth mark frequency and distribution at the FLK Zinj site reported by Blumenschine (Blumenschine, 1995, J. Hum. Evol. 29, 21-51), in which it was shown that long bone mid-shafts exhibited a high frequency of tooth marks, only explainable if felids had preceded hominids in carcass defleshing. The present work shows that previous estimates of tooth marks on the FLK Zinj assemblage were artificially high, since natural biochemical marks were mistaken for tooth marks. Revised estimates are similar to those obtained in experiments in which hyenas intervene after humans in bone modification. Furthermore, analyses of percussion marks, notches, and breakage patterns provide data which are best interpreted as the results of hominid activity (hammerstone percussion and marrow extraction), based on experimentally-derived referential frameworks. These multiple lines of evidence support previous analyses of cut marks and their anatomical distribution; all indicate that hominids had early access to fleshed carcasses that were transported, processed, and accumulated at the FLK Zinj site.     

Who was the first? An experimental application of carnivore and hominid overlapping marks at the Pleistocene archaeological sites

There are many types of evidence that provide information about methods for obtaining animal nutrients. Several researchers suggest that the main element to be considered is the skeletal representation of the different species identified in the faunal assemblage. This element must be associated to the animals’ age at death and the localisation of processing marks of the carcasses (both those of anthropic origin and those produced by carnivores). Occasionally, these marks coincide on the same point of the bone, giving cause for overlapping marks. These marks can be considered an aid more to identify the anthropic manner for obtaining animal recourses. However, these cases are very unusual at archaeological sites, and it is not always easy to identify which of the two predators has obtained the prey first. Through the experimental process presented in this article, we have observed diagnostic elements on overlapping marks that show the action sequence of the predators (hominids and carnivores) on carcasses. These experimental criteria were applied to different archaeological sites of the Lower and Middle Pleistocene in the Iberian Peninsula: Bolomor Cave (Valencia, Spain) and level TD10-1 and TD6-2 of Gran Dolina (Atapuerca, Burgos). In these assemblages, we were able to distinguish hunting and scavenging events through overlapping marks, providing a new element to the general interpretation of these sites.     

Adults only. Reindeer hunting at the middle palaeolithic site salzgitter lebenstedt, northern Germany

The Middle Palaeolithic site Salzgitter Lebenstedt (northern Germany), excavated in 1952, is well known because of its well-preserved faunal remains, dominated by adult reindeer (Rangifer tarandus). The archaeological assemblage accumulated in an arctic setting in an earlier part of the last (Weichsel) glacial (OIS5-3). The site is remarkable because of the presence of unique Middle Palaeolithic bone tools and the occurrence of the northernmost Neanderthal remains, but this paper focuses on an analysis of its reindeer assemblage. The results indicate autumn hunting of reindeer by Middle Palaeolithic hominids. After the hunt, carcasses were butchered and in subsequent marrow processing of the bones a selection against young and sub-adult animals occurred. Adults were clearly preferred, and from their bones, again, poorer marrow bones were neglected. This focus on primeness of resources has been documented in other domains of Neanderthal behaviour, but Salzgitter Lebenstedt is the best example yet known in terms of systematic and routinized processing of game. The Salzgitter Lebenstedt assemblage displays some remarkable similarities to the Late Glacial reindeer assemblages from the Ahrensburg tunnel valley sites. The subsequent review of the evidence on subsistence strategies from earlier periods of the European Palaeolithic shows that hunting of large mammals may have been a part of the behavioural repertoire of the Middle Pleistocene occupants of Europe from the earliest occupation onwards. At the same time, it is suggested that these early hunting strategies were incorporated in ways of moving through landscapes ("settlement systems") which were different from what we know from the middle parts of the Upper Palaeolithic onwards.     

Systematic butchering of fallow deer (Dama) at the early middle Pleistocene Acheulian site of Gesher Benot Ya'aqov (Israel)

Three assemblages of fallow deer (Dama sp.) bones excavated from the early middle Pleistocene (oxygen isotope stage 18) layers of the Acheulian site of Gesher Benot Ya'aqov, Israel, furnish evidence of systematic and repeated exploitation of complete carcasses by hominins. The excellent state of preservation of the bones and the presence of only minimal signs of carnivore involvement permit an investigation of the role of hominins as the primary agents responsible for the damage to these bones. Hominin expertise in dealing with fallow deer carcasses is manifested by cut marks, percussion marks, and hack marks on the bones. The archaeozoological analysis of the anatomical position and frequency of these marks suggests that carcass processing followed systematic practices that reflect an in-depth knowledge of fallow deer anatomy and a consistent behavioral strategy. These assemblages represent one of the earliest examples of methodological butchering practices in Eurasia. The evidence of carcass processing observed at Gesher Benot Ya'aqov resembles that seen in late Pleistocene sites in Israel, which were inhabited by modern humans. We interpret the Gesher Benot Ya'aqov data as indicating that the Acheulian hunters at the site (1) were proficient communicators and learners and (2) possessed anatomical knowledge, considerable manual skill, impressive technological abilities, and foresight.     

Disentangling Early Stone Age palimpsests: determining the functional independence of hominid- and carnivore-derived portions of archaeofaunas

Determining the extent to which hominid- and carnivore-derived components of fossil bone palimpsests formed independently of each other can provide valuable information to paleoanthropologists interested in reconstructing the foraging adaptations of hominids. Because stone tool cutmarks, hammerstone percussion marks, and carnivore tooth marks are usually only imparted on bone during nutrient extraction from a carcass, these bone surface modifications are particularly amenable to the types of analyses that might meet this goal. This study compares the percentage of limb bone specimens that preserve evidence of both hominid- and carnivore-imparted bone damage from actualistic control samples and several Plio-Pleistocene archaeofaunas, including new data from Swartkrans Member 3 (South Africa). We argue that this procedure, which elucidates the degree of hominid-carnivore independence in assemblage formation, will allow researchers to extract for focused analyses high integrity components (hominid and carnivore) from presumably low integrity sites. Comparisons suggest that the hominid- and carnivore-derived components from sites in Olduvai Gorge Bed II (Tanzania), the ST Site Complex at Peninj (Tanzania), and Swartkrans Member 3 formed largely independent of each other, while data from the FLK 22 Zinjanthropus (FLK Zinj) site (Olduvai Gorge Bed I) indicate significant interdependence in assemblage formation. This contrast suggests that some Early Stone Age assemblages (e.g., the Olduvai Gorge Bed II sites, the Peninj ST Site Complex, and Swartkrans Member 3) are probably more useful than others (e.g., FLK Zinj) for assessing the maximal carcass-acquiring abilities of early hominids; in such assemblages as those in the former set, sole hominid-contribution is more confidently discerned and isolated for analysis than in assemblages such as FLK Zinj.     

Long-distance carcass transport at Olduvai Gorge? A quantitative examination of Bed I skeletal element abundances

Relative abundances of skeletal elements at Plio-Pleistocene archaeological sites have long been interpreted to represent selective transport of portions of large prey. Models from optimal foraging theory suggest that the degree of carcass transport selectivity reflects transport constraints, particularly transport distance. A quantitative analysis of skeletal element abundances in five bone assemblages from Bed I, Olduvai Gorge, indicates that within the subset of elements most likely to resist attritional processes, there is no evidence for preferential transport of small or large mammals. The results suggest relatively low carcass transport costs and are most consistent with site formation models favoring short-distance carcass transport. The data are also consistent with the possibility that hominins were not responsible for transporting bones at some sites. Several Bed I assemblages, with the exception of FLK-Zinjanthropus, lack evidence of a functional relationship between flaked stone artifacts and the faunal remains, such as cut-marks or percussion-marks on bone. In conjunction with the skeletal part data, this suggests that hominin involvement with the bone assemblages was minimal at all sites but FLK-Zinjanthropus. The patterning at Bed I contrasts strongly with Middle Stone Age and Middle Paleolithic assemblages, which provide clear evidence for selective transport, suggesting higher transport costs and longer transport distances.     

Cutmarked bones from Pliocene archaeological sites at Gona, Afar, Ethiopia: implications for the function of the world's oldest stone tools

Newly recorded archaeological sites at Gona (Afar, Ethiopia) preserve both stone tools and faunal remains. These sites have also yielded the largest sample of cutmarked bones known from the time interval 2.58-2.1 million years ago (Ma). Most of the cutmarks on the Gona fauna possess obvious macroscopic (e.g., deep V-shaped cross-sections) and microscopic (e.g., internal microstriations, Herzian cones, shoulder effects) features that allow us to identify them confidently as instances of stone tool-imparted damage caused by hominid butchery. In addition, preliminary observations of the anatomical placement of cutmarks on several of the recovered bone specimens suggest that Gona hominids may have eviscerated carcasses and defleshed the fully muscled upper and intermediate limb bones of ungulates--activities that further suggest that Late Pliocene hominids may have gained early access to large mammal carcasses. These observations support the hypothesis that the earliest stone artifacts functioned primarily as butchery tools and also imply that hunting and/or aggressive scavenging of large ungulate carcasses may have been part of the behavioral repertoire of hominids by c. 2.5 Ma, although a larger sample of cutmarked bone specimens is necessary to support the latter inference.     

The Oldowan industry of Peninj and its bearing on the reconstruction of the technological skills of Lower Pleistocene hominids

The Oldowan technology has traditionally been assumed to reflect technical simplicity and limited planning by Plio-Pleistocene hominids. The analysis of the Oldowan technology from a set of 1.6-1.4 Ma sites (ST Site Complex) in Peninj adds new information regarding the curated behavior of early hominids. The present work introduces new data to the few published monographic works on East African Oldowan technology. Its relevance lies in its conclusions, since the Peninj Oldowan assemblages show complex technological skills for Lower Pleistocene hominids, which are more complex than has been previously inferred for the Oldowan stone tool industry. Reduced variability of tool types and complex use of cores for flaking are some of the most remarkable features that identify the Oldowan assemblages from Peninj. Hominids during this period seem to have already been experimenting with pre-determination of the flaked products from cores, a feature presently assumed to appear later in time. Planning and template structuring of flaked products are integral parts of the Oldowan at Peninj.     

Carcass transport decisions in Homo antecessor subsistence strategies

Pleistocene foragers used several prey acquisition and processing strategies. These strategies and their associated decisions are elucidated by taphonomic studies that cover animal transport, modifications by different agents and archaeological remains. Interpretative models of archaeological sites are by necessity based on natural and experimental observations. Ethno-archaeological data shows that several factors influenced decisions about carcass transport from the kill site to the home site. These factors often have little archaeological visibility. Díez et al. (1999) has previously interpreted the general characteristics of the macro-mammal remains from Gran Dolina Level TD6-2 (Sierra de Atapuerca, Burgos, Spain) as the result of anthropic accumulation, in which the anatomical profiles appeared to be the result of selective transport based on the animals’ weight. Recent taphonomic analysis has shown that carcasses with different weights may be subject to similar transport strategies, suggesting that other factors influenced these choices. The hominins that occupied TD6-2 (the TD6-2 hominin group), at least sometimes, transported large carcasses to the cave in their entirety, implying participation by groups of individuals in hunting parties. These individuals delayed their consumption of large amounts of food, instead moving it to Gran Dolina, where it was shared with other group members. These decisions are evidence of social cooperation and food sharing amongst early European hominins.     

Temporal resource partitioning mediates vertebrate coexistence at carcasses: The role of competitive and facilitative interactions

Unravelling how biodiversity is maintained despite species competition for shared resources has been a central question in community ecology, and is gaining relevance amidst the current biodiversity crisis. Yet, we have still a poor understanding of the mechanisms that regulate species coexistence and shape the structure of assemblages in highly competitive environments such as carrion pulsed resources. Here, we study how large vertebrates coexist in scavenger assemblages by adapting their diel activity at large ungulate carcasses in NW Spain. We used camera traps to record vertebrate scavengers consuming 34 carcasses of livestock and hunted wild ungulates, which allowed us to assess also differences regarding carcass origin. To evaluate temporal resource partition among species, we estimated the overlap of diel activity patterns and the mean times of each scavenger at carcasses. We recorded 16 species of scavengers, 7 mammals and 9 birds, and found similar richness at both types of carcasses. Birds and mammals showed contrasting diel activity patterns, with birds using carcasses during daytime (mean= 11:38 h) and mammals mostly at night (23:09 h). The unimodal activity patterns of scavengers showed asynchronous peaks among species. Subordinate species modified their activity patterns at carcasses used by apex species to reduce temporal overlap. Also, diel activity patterns of vultures closely followed those of corvids, suggesting facilitation processes in which corvids would enhance carcass detection by vultures. Two mammal species (12.5%) increased nocturnality at carcasses of hunted ungulates, which could be a response to human disturbance. Our results suggest that both temporal segregation and coupling mediate the coexistence of large vertebrates at carcasses. These mechanisms might lead to richer scavenger assemblages and thereby more efficient ones in driving critical ecosystem functions related to carrion consumption, such as energy and nutrient recycling and biodiversity maintenance.     

Raw material selectivity of the earliest stone toolmakers at Gona, Afar, Ethiopia

Published evidence of Oldowan stone exploitation generally supports the conclusion that patterns of raw material use were determined by local availability. This is contradicted by the results of systematic studies of raw material availability and use among the earliest known archaeological sites from Gona, Afar, Ethiopia. Artifact assemblages from six Pliocene archaeological sites were compared with six random cobble samples taken from associated conglomerates that record pene-contemporaneous raw material availability. Artifacts and cobbles were evaluated according to four variables intended to capture major elements of material quality: rock type, phenocryst percentage, average phenocryst size, and groundmass texture. Analyses of these variables provide evidence of hominid selectivity for raw material quality. These results demonstrate that raw material selectivity was a potential component of Oldowan technological organization from its earliest appearance and document a level of technological sophistication that is not always attributed to Pliocene hominids.     

Carcass size shapes the structure and functioning of an African scavenging assemblage

The particle size of the food resource strongly determines the structure and dynamics of food webs. However, the ecological implications of carcass size variation for scavenging networks structure and functioning have been largely overlooked. Here we investigate differences in scavenging patterns due to carcass size in a complex vertebrate scavenger community, Hluhluwe‐iMfolozi Park, South Africa, while taking into account seasonality. We monitored the consumption of three types of experimental carcasses: ‘small’ (< 10 kg), ‘medium’ (10–100 kg) and ‘large’ (> 100 kg). We employed general lineal models to explore the influence of carcass size on 1) scavenging network structure (scavenger species richness per carcass) and 2) functioning (carcass detection time, consumption time, consumption rate and percentage of carrion consumed). We also tested whether the structure of the scavenging network of each carcass size was nested, i.e. whether the scavenging assemblage in species‐poor carcasses was a subset of the assemblage consuming species‐rich carcasses. We found strong evidence indicating that carcass size is a major factor governing the associated scavenger assemblage. Scavenger species richness per carcass and carcass consumption time and rate increased with carcass size, while carcass detection time and percentage of carrion biomass consumed were negatively related to carcass size. Strikingly, most of the carrion biomass was consumed by facultative scavengers, represented by large mammalian carnivores, rather than by obligate scavengers (i.e. vultures). Scavenging network nestedness tended to be higher at larger carcasses, and nestedness was sensitive to the removal of the most connected species in the network (spotted hyena) rather than vultures. When comparing scavenging and predation assemblages, crucial size‐dependent differences emerge. Also, we identified a traditionally ignored mechanism by which hunting large prey could be relatively less profitable for predators, namely the costs associated with competition from scavengers and decomposers.     

Earliest Archaeological Evidence of Persistent Hominin Carnivory

The emergence of lithic technology by ∼2.6 million years ago (Ma) is often interpreted as a correlate of increasingly recurrent hominin acquisition and consumption of animal remains. Associated faunal evidence, however, is poorly preserved prior to ∼1.8 Ma, limiting our understanding of early archaeological (Oldowan) hominin carnivory. Here, we detail three large well-preserved zooarchaeological assemblages from Kanjera South, Kenya. The assemblages date to ∼2.0 Ma, pre-dating all previously published archaeofaunas of appreciable size. At Kanjera, there is clear evidence that Oldowan hominins acquired and processed numerous, relatively complete, small ungulate carcasses. Moreover, they had at least occasional access to the fleshed remains of larger, wildebeest-sized animals. The overall record of hominin activities is consistent through the stratified sequence – spanning hundreds to thousands of years – and provides the earliest archaeological evidence of sustained hominin involvement with fleshed animal remains (i.e., persistent carnivory), a foraging adaptation central to many models of hominin evolution.     

Archaeological predictions for hominid land use in the paleo-Olduvai Basin, Tanzania, during lowermost Bed II times

We present a preliminary predictive model of Oldowan stone artefact and scavenged larger mammal bone assemblages for 11 landscape facets modeled earlier to occur across a large portion (>300 km²) of the paleo-Olduvai Basin during lowermost Bed II times. This second phase of model-building is based on our earlier characterizations of the basin's landscape ecostructure and the inter-facet distribution of key resources and hazards probably encountered by Late Pliocene hominids (Peters & Blumenschine, 1995, 1996). Our current extension of the model of hominid–landscape interactions specifies additional theoretical components, including: (1) the assumed capabilities of Oldowan hominids (presumablyHomo habilis, primarily); (2) the landscape-facet-specific tasks they carried out; (3) the immediate stone and bone task residues they produced; and (4) the predicted composition, condition, density, and clustering of stone artefact and butchered and unbutchered bone assemblages for each facet. We develop ecological linkages between these new and formerly reported modeling components, the most fundamental of which is the facet-specific degree of tree/shrub cover abundance, and the correlated degree of competition among larger carnivores and hominids for scavengeable larger mammal carcasses. These factors condition variability among landscape facets in scavenging opportunities encountered by hominids, which in our model is the major predictor of bone and stone artefact assemblage composition. The predictive value of scavenging reflects the bias of paleoanthropological traces toward technology and butchery in their landscape context, but the model is surprisingly insensitive to what are usually thought to be critical social components of hominid land use. The predictions for the traces of hominid–landscape interactions modeled herein can be tested in the future against the landscape archaeological sample being excavated from lowermost Bed II by the Olduvai Landscape Paleoanthropology Project.     

Dry wildebeest carcasses in the African savannah: the utilization of a unique resource

Utilization of dry wildebeest carcasses by spotted hyaena in an African savannah setting is investigated. Four transects of varying length (3–10 km) were located in the Maasai Mara National Reserve, Kenya. Measuring carcass weight changes biweekly over a period of 9 months monitored hyaena use of dry wildebeest carcasses. Nutrient quality of dry carcasses (skin and bone) and of flesh was analysed in the laboratory using the material collected in the field. Contrary to common expectation, carcass weight change was significantly higher when the migrants were present in the Reserve than when they were absent in all transects monitored. This is thought to indicate greater carcass utilization during periods of relative prey scarcity caused by the migratory herd movements within the Reserve, and perhaps, the territorial nature of spotted hyaenas. Nutrient analysis indicated that dry carcasses contain significant amounts of protein, carbohydrates and minerals, although lacking in fats compared with flesh. The opportunistic nature and evolution of a digestive physiology in this species capable of utilizing dry carcasses appears to have important adaptive value in an environment frequented by thousands of migrant herbivores for short periods every year.     

Disentangling faunal skeletal profiles. A new probabilistic framework

Abstract

Faunal skeletal profiles from archaeological assemblages have been long analysed regarding differential transport of carcasses to infer hunting preferences, human mobility, or even dietary stress. However, the existence of several possible accumulating agents, together with the effect of bone attrition, is known to introduce a potential bias, thus hindering the possibilities of meaningful concussions. In order to overcome this problem, several methods were proposed during the late 90s and early 2000’s, although a consensus was not reached, mainly because the different approaches were based on a certain initial hypothesis that significantly affected the output. Building on that previous experience, a new methodological framework is proposed and compared here. Moving from rather deterministic techniques, a Bayesian alternative approach based on a Monte Carlo Markov Chain sampling is presented and applied to several ethnographic and Pleistocene key sites. This new method makes use of the available information to constrain the possible degrees of attrition and carcass processing strategies, leading to easily comparable results.     

Amplified Fragment Length Polymorphism Fingerprinting of Pseudomonas Strains from a Poultry Processing Plant

Molecular typing has been used previously to identify and trace dissemination of pathogenic and spoilage bacteria associated with food processing. Amplified fragment length polymorphism (AFLP) is a novel DNA fingerprinting technique which is considered highly reproducible and has high discriminatory power. This technique was used to fingerprint 88 Pseudomonas fluorescens and Pseudomonas putida strains that were previously isolated from plate counts of carcasses at six processing stages and various equipment surfaces and environmental sources of a poultry abattoir. Clustering of the AFLP patterns revealed a high level of diversity among the strains. Six clusters (clusters I through VI) were delineated at an arbitrary Dice coefficient level of 0.65; clusters III (31 strains) and IV (28 strains) were the largest clusters. More than one-half (52.3%) of the strains obtained from carcass samples, which may have represented the resident carcass population, grouped together in cluster III. By contrast, 43.2% of the strains from most of the equipment surfaces and environmental sources grouped together in cluster IV. In most cases, the clusters in which carcass strains from processing stages grouped corresponded to the clusters in which strains from the associated equipment surfaces and/or environmental sources were found. This provided evidence that there was cross-contamination between carcasses and the abattoir environment at the DNA level. The AFLP data also showed that strains were being disseminated from the beginning to the end of the poultry processing operation, since many strains associated with carcasses at the packaging stage were members of the same clusters as strains obtained from carcasses after the defeathering stage.