Winter Survival of Wild Turkey Females in Central Minnesota

Abstract: There is interest in expanding eastern wild turkey (Meleagris gallopavo silvestris) populations north of their current range. We hypothesized that winter survival and food availability are primary determinants in setting the northern extent of wild turkey distribution. To test our hypothesis, we translocated wild turkey females north of their present range into central Minnesota, USA, and compared survival in areas with supplemental food in the form of corn food plots versus areas with no supplemental food. During 2 winters with below-average snow, winter survival was higher for females with supplemental food. In one winter with above-average snow depths, survival was extremely low even with supplemental food. Supplemental food could augment survival during mild winters if wildlife managers arrange with farmers to, annually, retain standing corn near roosting habitat, but food plots may only partially offset effects of deep snow. Managers should critically evaluate northern habitats, long-term costs of sustained feeding, and potential outcomes of concentrating animals and introducing wild animals into new ecosystems. Winter survival may delimit the northern range of wild turkeys, though annual survival rates may also be important and need further research.     

Methicillin-resistant Staphylococcus aureus in animals

Methicillin-resistant Staphylococcus aureus (MRSA) is a critically important human pathogen that is also an emerging concern in veterinary medicine and animal agriculture. It is present in a wide range of animal species, including dogs, cats, rabbits, horses, cattle, pigs, poultry, and exotic species, both as a cause of infection and in healthy carriers. Identification of MRSA in various species and in food has led to concerns about the roles of animals, both pets and livestock, in the epidemiology of MRSA infection and colonization in humans. There is evidence of the role of food animals in human MRSA infections in some countries and of pets as a possible source of human infection. Some groups of individuals who work closely with animals, such as veterinarians, have high MRSA colonization rates. This article includes discussions of MRSA in human medicine, animals, and food, as well as its interspecies transmission, colonization, infection, strains, and affected populations. However, clear answers are lacking in many of these areas and limited studies may lead to premature conclusions. It is certain that animals are a source of human MRSA infection in some circumstances--but humans may also serve as sources of infection in animals. Changes in the epidemiology of MRSA in one species may be reflected in changes in other species. The true scope of MRSA in animals and its impact on human health are still only superficially understood, but it is clear that MRSA is a potentially important veterinary and public health concern that requires a great deal more study to enhance understanding and effective response.     

Which senses play a role in nonhuman primate food selection? A comparison between squirrel monkeys and spider monkeys

In order to optimize foraging efficiency and avoid toxicosis, animals must be able to detect, discriminate, and learn about the predictive signals of potential food. Primates are typically regarded as animals that rely mainly on their highly developed visual systems, and little is known about the role that the other senses may play in food selection. It was therefore the aim of the present study to assess which senses are involved in the evaluation of food by two species of New World primates: the squirrel monkey and the spider monkey. To this end, six animals per species were repeatedly presented with both familiar and novel food items, and their behavior was videotaped and analyzed. To obtain a further indication of the relative importance of visual and chemosensory cues, the animals were also presented with familiar food items that were experimentally modified in color, odor, or both color and odor. The results demonstrate that squirrel monkeys and spider monkeys use olfactory, gustatory, and tactile cues in addition to visual information to evaluate novel food, whereas they mainly inspect familiar food items visually prior to consumption. Our findings also show that in both species the use of nonvisual cues decreased rapidly with repeated presentations of novel food, suggesting a fast multimodal learning process. Further, the two species clearly differ in their relative use of nonvisual cues when evaluating novel or modified food, with spider monkeys relying more on olfactory cues than squirrel monkeys, and squirrel monkeys relying more on tactile cues compared to spider monkeys.     

The functional basis of frequency-dependent food selection

Various animals have been observed to select food in a way that changes according to the relative frequency of the different foods available. Sometimes only the strength of selection varies, its direction remaining constant, but sometimes the direction of selection also changes. Selection of a food may be more intense as that food becomes rarer, or vice versa. I discuss here the situations in which animals, particularly predators, may maximize their feeding efficiency by behaving in ways that result in frequency-dependent selection of their food. These include cases in which different types of prey occupy different ecological niches, those in which there are benefits or costs to mixed diets for the predator, those in which rarer types of prey provide easier targets, those in which the different types of prey provide unequal benefits to the animal eating them, those in which direct comparison of the benefits is possible, those in which sampling is necessary because the benefits are unknown, and Batesian and other mimicries. Frequency-dependent selection of food is likely to be common and widespread: to assume frequency independence, without testing, may often be misleading.     

内蒙古东部地区狼的食性初步研究

本文采用粪便分析法和食痕分析法对内蒙古东部狼的食性进行初步研究。结果表明, 该地区狼的主要食物是大、中型有蹄类（出现频率53.8%, 相对生物量85.17%）, 粪便中家畜出现频率为40.3%, 相对生物量为75.67%。该地区狼的食性同黑龙江狼的食性相比, 存在地区差异。通过饲喂实验, 提出狼粪便中所含猎物的干重与鲜重间的线性回归方程为Y=2.76+0.02x（r=0.99）, 应用此方程可估计出狼消耗各种猎物的相对生物量和数量。在该地区狼对家畜危害比较严重, 要适当猎取同时也应保持其适当数量。     

A mathematical model of the food-consumer system I. A case without food replenishment

A simple mathematical model was proposed to describe the dynamics of a food-consumer system. The model was based on the Logistic Theory and consisted of Eqs. (4), (5) and (6). The model was divided into the following three cases for further analyss; i) without food supply except at the initial time, ii) with continuous food supply at a constant rate, and iii) with food supply at varying rates. Only the first model was dealth with in this paper. The assumptions of the model 1 are that a definite amount of food is given only once at the initial time and only the feeding by animals is responsible for the decrease of food, and that the rate of decrease is proportional to the amount of animals. It is also assumed that the growth of animal population is represented by the logistic curve, and that the upper limit of the population is proportional to the amount of food at that time. For simplicity the parameters of basic differential equations are assumed to be constant throughout the time course. Analytical solutions of this non-linear model were given by Eqs. (8), (9), (10) and (11). The properties of time course of the food amount and consumer population were discussed from the mathematical and biological points of view. The method of the estimation of the three constants λ,b, and c from the experimental data was also suggested. Since we had no available data for animal populations, we applied the model, regarding reserve substance as x and new plant body as y, to the data of the initial growth of Azuki bean plant in the dark. This model is very simple, but it may be useful for analyzing the behavior of food-consumer system. And it may give some clue to the analysis of the more complex systems.     

Protocol to refine intestinal motility test in mice

We propose a new protocol intended to conform to the 3Rs (replacement, reduction, and refinement) principle, using animals fasted for 3 h to control intestinal motility, which reduced stress in the animals. In this new protocol, mice are deprived of food for a short time (3 h) and are not killed. The mice are observed until evacuation containing charcoal is observed, and the experimental results are based on the charcoal evacuation time. The present study may aid the formulation of recommendations that can be included in revised guidelines relating to the fasting time of mice. This new concept of an intestinal motility test conforms with respectful science.     

Effects of somatostatin on food intake in rats

We examined the possibility that somatostatin, a tetradecapeptide distributed in the gut and the central nervous system, may influence food intake and behavior in rats. Although intravenously infused somatostatin did not alter food intake in 8 hour fasted rats, intracerebroventricularly infused somatostatin resulted in a biphasic response, first increasing then decreasing food intake. We also observed that the effects of somatostatin vary depending upon whether animals are fed or fasted. In fed rats, food intake was decreased, while in fasted rats food intake was increased. These results suggest that somatostatin can act in the central nervous system to stimulate appetite; but that other factors, possibly related to gut motility or clearance, may inhibit further feeding once the stomach is full.     

Recycling Biowaste – Human and Animal Health Problems

Biowaste from the food chain is of potential benefit to use in agriculture. Agriculture in general and organic farming in particular needs alternative plant nutrients. However, the quality concerning hygiene and soil contaminants must be assured. This recycling has to be regulated in a way that harmful effects on soil, vegetation, animals and man are prevented.The problems with heavy metals and organic contaminants have been focused on. Still, maximum threshold values are continuously discussed to avoid an increase of soil concentrations. The effect on the ecosystems of residues from use of medicines needs further attention. There is also a risk for a spread of antibiotic resistant micro-organisms in the environment and then to animals and man. Infectious diseases may be spread from biowaste and new routes of disease transmission between animals and humans can be created. Zoonotic diseases in this context play a central role. Pathogens recently introduced to a country may be further spread when biowaste is recycled. The very good health status of domestic animals in the Nordic countries may then quickly change. The quality of biowaste is of enormous importance if biowaste is to gain general acceptance for agricultural use, especially for organic production. A balance needs to be maintained between risk and advantage for its use.     

A conceptual framework for nonkin food sharing: timing and currency of benefits

Many animal species, from arthropods to apes, share food. This paper presents a new framework that categorizes nonkin food sharing according to two axes: (1) the interval between sharing and receiving the benefits of sharing, and (2) the currency units in which benefits accrue to the sharer (especially food versus nonfood). Sharers can obtain immediate benefits from increased foraging efficiency, predation avoidance, mate provisioning, or manipulative mutualism. Reciprocity, trade, status enhancement and group augmentation can delay benefits. When benefits are delayed or when food is exchanged for nonfood benefits, maintaining sharing can become more difficult because animals face discounting and currency conversion problems. Explanations that involve delayed or nonfood benefits may require specialized adaptations to account for timing and currency-exchange problems. The immediate, selfish fitness benefits that a sharer may gain through by-product or manipulative mutualism, however, apply to various food-sharing situations across many species and may provide a simpler, more general explanation of sharing.     

Structure-guided foraging in long-tailed macaques

The aim of this study was to identify some of the cues that macaques follow when they search for new food sites. A social group of 37 long-tailed macaques was confined to a holding cage while an experimenter concealed food in an outdoor enclosure according to one of the following rules: (1) along the edge of a visible environmental border, (2) within structures of the same general type, or (3) along an ecologically irrelevant, invisible straight line. To provide the animals with a cue for detecting the rule, three piles of visible food were also presented according to the rule. Each of the 60 trials involved a different location in the 880 m² enclosure. The animals showed clear evidence of utilizing the first two rules from the outset of testing and the third rule about five trials. The animals found concealed food along environmental borders and within matching objects more quickly than along invisible lines. They also showed a rapid improvement in food finding on the invisible line. The results suggest that long-tailed macaques extend their search for food to a given class of environmental structure rather than exclusively by pure spatial gradients. © 1996 Wiley-Liss, Inc.     

Food deprivation inhibits estrous behavior in hormone-treated Syrian hamsters despite elevated estradiol levels

Estradiol and progesterone (P) induce female mammalian reproductive behaviors, which are, in turn, sensitive to food availability. When ovariectomized, steroid-primed hamsters are food deprived for 48 h, estrous behavior is suppressed. While this suppression of estrous behavior may be due to alterations in neural steroid receptor levels, it is also possible that decreased levels of circulating estradiol could be involved in mediating this suppression. Ovariectomized Syrian hamsters given varying doses of estradiol benzoate (EB) and P were tested to determine whether increasing doses of sex steroids would overcome the suppressive effects of food deprivation on estrous behavior. As expected, lordosis duration decreased in food-deprived animals. Increasing the levels of EB, but not P, increased lordosis duration in the food-deprived animals so that animals who were given 20 microg of EB had lordosis durations significantly longer than food-deprived hamsters that received 1.5 microg and 2.5 microg EB. Following an injection of 2.5 microg of EB, food-deprived hamsters actually had higher circulating levels of estradiol than ad libitum-fed animals. Therefore, increasing circulating levels of estradiol can increase lordosis durations in fasted animals; however, the suppression of estrous behavior occurs despite increased circulating estradiol levels in ovariectomized, steroid-treated animals. The most parsimonious explanation for this phenomenon is a deprivation-induced reduction in neural responsiveness to estradiol.     

Food ingestion and circadian rhythmicity

Feeding is organised within the 24-h of the light - dark (LD) cycle. Food is ingested in a circadian manner in nature and in laboratory animals kept under constant conditions. The circadian rhythmicity in food ingestion is driven by a biological clock located in the suprachiasmatic nuclei (SCN) of the hypothalamus. The circadian organisation of food ingestion not only allows animals to live in harmony with their environment but food intake could also act as a zeitgeber for other rhythmic functions. Lesions in the area of the SCN result in the loss of most rhythmic functions as well as to a disrupted circadian rhythmicity of food and water intake. These findings, together with observations from daytime feeding experiments conducted in nocturnal animals, suggest that food intake may serve as a temporal signal for some peripheral organs to oscillate in phase with the SCN. This paper overviews and discusses how food intake interacts with the circadian system.     

A Non-Lévy Random Walk in Chacma Baboons: What Does It Mean?

The Lévy walk is found from amoebas to humans and has been described as the optimal strategy for food research. Recent results, however, have generated controversy about this conclusion since animals also display alternatives to the Lévy walk such as the Brownian walk or mental maps and because movement patterns found in some species only seem to depend on food patches distribution. Here I show that movement patterns of chacma baboons do not follow a Lévy walk but a Brownian process. Moreover this Brownian walk is not the main process responsible for movement patterns of baboons. Findings about their speed and trajectories show that baboons use metal maps and memory to find resources. Thus the Brownian process found in this species appears to be more dependent on the environment or might be an alternative when known food patches are depleted and when animals have to find new resources.     

The place of farm animal species in the new genomics world of reproductive biology

Reproductive studies on farm animals have been part of the underpinnings that have led to the ready availability of low cost, safe, and nutritious food in the developed world. They have also made a significant contribution to reproductive medicine. Yet at a time when world demand for food is increasing and the National Institutes of Health budget is set to double between 1998 and 2003, funding for animal agriculture remains low, erratic, and politically vulnerable. There are also those who question whether the food animals have value any longer as comparative models for studying reproduction as it related to human health and well being. In this paper I describe how such research is presently funded at the federal level and discuss why support for agricultural science is in decline, despite many unmet needs. I then suggest that the human genome project and the developing areas of comparative gene mapping and functional genomics are beginning to provide new impetus to studies on farm animal species. Finally I argue that although rodents and, above all, the mouse, with all its genetic advantages, occupy lofty positions as models for studying reproductive processes and their abnormalities in the human, there will continue to be a need to take a broader comparative approach that will inevitably involve farm animals.     

The Lama and the Jumbo‐Jet: Report on a Tibetan meditation‐group in Switzerland

The Huaulu people of Seram (Eastern Indonesia) say that it is taboo for them to eat the animals which they feed. The reason is that sharing food with them implies attributing to them the status of fellow social beings. This status implies in turn a degree of personhood. Persons may not be treated as the ultimate thing: food. The article shows that the principle “if we feed them we do not feed on them” applies differently to domesticated species and to wild ones. If some individuals of a domesticated species are raised by the Huaulu, the whole species becomes taboo to eat. But in the case of wild species the taboo is limited to the individuals which are actually raised. The article also shows that the principle is not the only reason for the taboo on domesticated animals, but a shorthand for a variety of other reasons that have to do with the place of those animals in Huaulu society.     

Food transfers to young and mates in wild owl monkeys (Aotus azarai)

Accounts of food sharing within natural populations of mammals have focused on transfers to offspring or transfers of food items that are difficult to obtain (such as meat). Five groups of socially monogamous owl monkeys (Aotus azarai azarai) in Formosa, Argentina were observed during 107 hr to determine the pattern of food sharing under natural conditions. There were a total of 42 social interactions involving food with food being transferred on eight occasions. Adult males transferred food to young more often than did adult females. All types of food that were readily obtained and eaten by all age/sex classes were transferred to young. Adult females also transferred food to their mates. This type of food sharing is very rare among animals and may have social benefits specific to monogamous mammals with paternal care.     

Rimonabant: the first therapeutically relevant cannabinoid antagonist

The present paper synthetically reviews the multiple experimental lines of evidence indicating the ability of the prototypic cannabinoid CB(1) receptor antagonist, rimonabant (also known as SR 141716), to suppress the reinforcing/rewarding properties of different drugs of abuse, including cocaine, heroin, nicotine and alcohol, in laboratory rodents. This paper also reviews the data demonstrating that rimonabant reduces food intake and body weight in laboratory animals and humans. Taken together, the data reviewed here suggest that rimonabant may constitute a new and potentially effective medication for the treatment of drug addiction and obesity-related disorders.     

A lifetime perspective on foraging and mortality

Food intake carries many potential risks which may impair an animal's reproductive success not only in the current breeding cycle, but also for the rest of its lifetime. We examine the lifetime trade-off between the costs and benefits of food intake by presenting a simple animal foraging model, where each unit of food eaten carries with it a risk of mortality. We show that the optimal food intake rate over an animal's lifetime, for both semelparous and iteroparous animals, is not maximal. Instead, animals are required to strike a balance between the immediate reproductive benefits of gathering food and the future reproductive costs incurred by the food's mortality risk. This balance depends upon the lifespan of the animal as well as the nature of the risk. Different mortality risks are compared and it is shown that a mortality risk per unit time spent foraging is not, in general, equivalent to a mortality risk per unit of food consumed. The results suggest that a mortality risk per unit of food consumed, such as that presented by the presence of a toxin or of a parasite in the diet, has important consequences for feeding behaviour and is a possible factor involved in food intake regulation.