Ontogeny of aquatic behaviours in Antarctic fur seal (Arctocephalus gazella) pups in relation to growth performances at Kerguelen Islands

In diving marine predators, such as pinnipeds, the development of diving and foraging skills prior to weaning might be critical to post-weaning survival. Here, we examined the effect of pup mass growth on the amount of time devoted to aquatic activities and the dive performance of Antarctic fur seal, Arctocephalus gazella, pups on Kerguelen Island. Maternal attendance and mass-specific growth rate were assessed for 85 pups. Two types of monitoring were applied: visual observations of behaviours for 60 pups and the deployment of time-depth recorders (TDRs) on 19 female pups. At approximately 2 months of age, pups demonstrated minimal diving behaviour, but displayed considerable aquatic activity. While mothers were foraging at sea, pups fasted on land (6.0 ± 1.3 d). As the mass-specific growth rate was different between sexes, only data on female pups were analysed (n = 31). Mass-specific growth rate was related to maternal attendance patterns and impacted the amount of time allocated by pups to aquatic activities. The time spent in the water by pups was quadratically related to fasting progress. This study shows the importance of growth and fasting progress on the quantity of time pups devoted to aquatic activities. Our results suggest that greater post-weaning survival of heavier pups may be due not only to their greater body reserves, as reported in several studies, but also possibly to from their greater aquatic skills and physiological adaptations developed during the suckling period.     

Size and experience matter: diving behaviour of juvenile New Zealand sea lions (Phocarctos hookeri)

The diving ability of juvenile animals is constrained by their physiology, morphology and lack of experience, compared to adults. We studied the influences of age and mass on the diving behaviour of juvenile (2–3-year-old females, n = 12; 3–5-year-old males, n = 7) New Zealand (NZ) sea lions (Phocarctos hookeri) using time–depth recorders (TDRs) from 2008 to 2010 in the NZ subantarctic Auckland Islands. Diving ability (e.g. dive depth, duration and bottom time per dive) improved with age and mass. However, the percentage of each dive spent at the bottom, along with percentage time at sea spent diving, was comparable between younger and lighter juveniles and older and heavier juveniles. These suggest that younger and older juveniles expend similar foraging effort in terms of the amount of time spent underwater. Only, 5-year-old male juveniles dove to adult female depths and durations and had the highest foraging efficiency at depths >250 m. It appears that juvenile NZ sea lions attain adult female diving ability at around 5 years of age (at least in males), but prior to this, their performance is limited. Overall, the restricted diving capabilities of juvenile NZ sea lions may limit their available foraging habitat and ability to acquire food at deeper depths. The lower diving ability of juvenile NZ sea lions compared to adults, along with juvenile-specific constraints, should be taken into consideration for the effective management of this declining, nationally critical species.     

Diving behaviour of the Shy Albatross Diomedea cauta in Tasmania: initial findings and dive recorder assessment

The diving behaviour of the Shy Albatross Diomedea cauta was investigated using archival time-depth recorders (TDRs) and maximum depth gauges (MDGs). Data from birds carrying multiple devices and from diving simulations indicated that the degree of correspondence between TDRs and MDGs varied with the dive depth, duration and frequency, as well as with body placement. The MDGs were the most reliable when the diving depth was greater than 0.5 m, when the diving frequency was low and when gauges were placed on the birds' backs. The TDRs were used during late incubation and early chick rearing in 1994. Fifty-two dives (0.4 m) were recorded during 20 foraging trips of 15 individuals. The majority of dives were within the upper 3 m of the water column and lasted for less than 6 s. However, dives to 7.4 m and others lasting 19 s were recorded. The albatrosses dived between 07.00 h and 22.00 h, with peaks in their diving activity near midday and twilight. Mean diving depth varied throughout the day. with the deepest dives occurring between 10.00 h and 12.00 h. Two dive types were identified on the basis of the relationship between dive depth and descent rate. Plunge dives were short (5 s), and the birds reached a maximum depth of 2.9 m. Swimming dives were both longer and deeper. The characteristics of Shy Albatross plunge dives were similar to those of gannets Morus spp., which are known to be proficient plunge divers. Swimming dives suggest that Shy Albatrosses actively pursue prey underwater.     

FORAGING DEPTHS OF SEA OTTERS AND IMPLICATIONS TO COASTAL MARINE COMMUNITIES

We visually observed 1,251 dives, of 14 sea otters instrumented with TDRs in southeast Alaska, and used attribute values from observed dives to classify 180,848 recorded dives as foraging (0.64), or traveling (0.36). Foraging dives were significantly deeper, with longer durations, bottom times, and postdive surface intervals, and greater descent and ascent rates, compared to traveling dives. Most foraging occurred in depths between 2 and 30 m (0.84), although 0.16 of all foraging was between 30 and 100 m. Nine animals, including all five males, demonstrated bimodal patterns in foraging depths, with peaks between 5 and 15 m and 30 and 60 m, whereas five of nine females foraged at an average depth of 10 m. Mean shallow foraging depth was 8 m, and mean deep foraging depth was 44 m. Maximum foraging depths averaged 61 m (54 and 82 for females and males, respectively) and ranged from 35 to 100 m. Female sea otters dove to depths ≤20 m on 0.85 of their foraging dives while male sea otters dove to depths ≥45 m on 0.50 of their foraging dives. Less than 0.02 of all foraging dives were >55 m, suggesting that effects of sea otter foraging on nearshore marine communities should diminish at greater depths. However, recolonization of vacant habitat by high densities of adult male sea otters may result in initial reductions of some prey species at depths >55 m.     

Commensal association of the common kingfisher with foraging Eurasian otters

Positive interactions between birds and mammals are a fascinating aspect of animal behaviour. Feeding associations may consist of local enhancement or facilitation, and in the latter case, of commensalism or mutualism depending on the benefits received by the facilitator. We report here on a previously undescribed feeding association between piscivorous birds and Eurasian otters Lutra lutra. In Spain, common kingfisher Alcedo atthis and grey heron Ardea cinerea were observed closely following foraging otters and benefited from feeding opportunities provided by these. Behavioural observations of otters in central Spain (28.4 hr; 19 days) revealed that an association with kingfishers occurred in 33% of otter foraging events (n = 92). Simultaneous observations in northern Spain (14.2 hr; 16 days) showed an association between otters and kingfishers or grey herons in 41.6% and 11.7% of otter foraging events (n = 77), respectively. The association probability between kingfishers and otters increased significantly when otters foraged closer to the shore and on small fish rather than other prey (crayfish or large fish). Birds fed on prey remain left by the feeding otters, on small fish captured by otters when these were satiated and playing, or on prey displaced by otters. Our observations are consistent with facilitation and commensalism: piscivorous birds gained feeding opportunities provided by the otters, with no apparent costs or benefits to the latter. Similar feeding associations have been described between other species of otters and piscivorous birds (kingfishers, herons, egrets, storks) in Asia, South America and Southern Africa, but had not yet been described in Europe. The occurrence of piscivorous bird–otter associations in different species and regions suggests that this commensalism may be often overlooked but widespread. We have shown that the association can be frequent and is context‐dependent, with benefits for associating birds depending on otters´ behaviour and targeted prey.     

Divergent diving behavior during short and long trips of a bimodal forager,the little auk Alle alle

The purpose of this study was to characterize for the first time seabird diving behavior during bimodal foraging. Little auks Alle alle, small zooplanktivorous Alcids of the High Arctic, have recently been shown to make foraging trips of short and long duration. Because short (ST) and long trips (LT) are thought to occur in different locations and serve different purposes (chick‐ and self‐feeding, respectively) we hypothesized that foraging differences would be apparent, both in terms of water temperature and diving characteristics. Using Time Depth Recorders (TDRs), we tested this hypothesis at three colonies along the Greenland Sea with contrasting oceanographic conditions. We found that diving behavior generally differed between ST and LT. However, the magnitude of the disparity in diving characteristics depended on local foraging conditions. At the study site where conditions were favorable, diving behavior differed only to a small degree between LT and ST. Together with a lack of difference in diving depth and ocean temperature, this indicates that these birds did not increase their foraging effort during ST nor did they travel long distances to seek out more profitable prey. In contrast, where local foraging conditions were poor, birds increased their diving effort substantially to collect a chick meal during ST as indicated by longer, more U‐shaped dives with slower ascent rates and shorter resting times (post‐dive intervals and extended surface pauses). In addition, large differences in diving depth and ocean temperature indicate that birds forage on different prey species and utilize different foraging areas during LT, which may be up to 200 km away from the colony. Continued warming and deteriorating near‐colony foraging conditions may have energetic consequences for little auks breeding in the eastern Greenland Sea.     

Making it through the first year: Ontogeny of movement and diving behavior in harbor seals from Svalbard,Norway

Phocid seal pups must learn successful survival strategies, largely independently, following their abrupt weaning at a relatively young age. To explore the ontogeny of aquatic skills, space use and first‐year habitat choices made by harbor seals, pups (n = 30) were instrumented with satellite relay data loggers (SRDLs) in Svalbard, Norway in 2009 and 2010. Initially, the pups had small home ranges and showed rapid changes in their activity budgets and diving capabilities, displaying steep linear increases in diving depth and duration and in the amount of time spent diving. Most pups underwent an abrupt shift in movement patterns at ca. 50 d of age, which likely marked the end of the postweaning fast. Around this same time, the steep progression in diving performance slowed, though longer, deeper dives gradually became the norm. However, bottom time, ascent and descent rates, and postdive recovery times remained stable after the postweaning fast, suggesting that most aquatic skill acquisition was completed during the first months of life. Few clear effects of environmental variables such as upwelling phenomenon, which are known to influence the diving behavior of adults from the same population, were detected in the diving patterns of pups.     

The influence of wave exposure on the foraging activity of marine otter, <Emphasis Type="Italic">Lontra felina</Emphasis> (Molina, 1782) (Carnivora: Mustelidae) in northern Chile

The marine otter Lontra felina has been said to prefer wave-exposed habitats over more protected sites in response to a greater prey abundance in exposed habitat. We examined how the foraging activity of L. felina is affected by the regime of wave exposure and prey availability at Isla Choros, northern Chile. Through focal sampling we recorded time spent by otters in foraging, the duration of dives, and the hunting success on a wave-exposed and a wave-protected site on the island. In addition, we quantified the abundance of prey in both habitats. Marine otters spent more time foraging in the wave-protected site compared with the wave-exposed habitat. Successful dives reached 26.9% in the wave-exposed habitats, and 38.2% in the wave-protected habitat. Foraging dives were 18% shorter in wave-exposed as compared with wave-protected habitat. Numerically, available prey did not differ significantly with habitat. Our results are more consistent with the hypothesis that wave-exposed habitats represent a sub-optimal habitat to foraging marine otters. Marine otters’ use of wave-exposed patches through northern and central Chile coastal areas probably reflects a low availability of suitable protected areas and greater human disturbance of more protected habitat.     

Seasonal and annual variation in the diving behaviour of Hutton's shearwater (Puffinus huttoni)

ABSTRACT

With the development and implementation of tracking technology, we are now able to monitor the foraging behaviour of seabirds while at sea. Time-Depth Recorders (TDRs) were fitted to Hutton's shearwaters (Puffinus huttoni), an endangered endemic New Zealand species, to measure how diving behaviour varies over the breeding cycle. Hutton's shearwaters (～350?g) dive up to 339 times per day (average 68.8) at depths to 35?m (average 5.6?m), and for periods up to 60?s (average 19.2?s). Incubating birds dived deeper than birds feeding chicks, and a significant difference in diving depth and dive duration were detected at different times of the day. Neither dive frequency nor dive duration differed significantly between years, but there was some annual variation in dive depths. The temporal variation we observed in the diving behaviour of Hutton's shearwaters suggests they are likely to exploit different types of pelagic prey at different stages in their breeding cycle. With on-going changes in the marine environment, monitoring changes in feeding behaviour using TDRs may provide a way to assess environmental change and improve the conservation of this species.     

Foraging tactics of chick-rearing Crozet shags: individuals display repetitive activity and diving patterns over time

It is in the interest of resident and long-lived benthic foragers to learn to apply efficient foraging tactics throughout their lifetime, thus increasing their individual efficiency. To test whether individuals are capable of applying an individual-specific foraging pattern, we checked for the existence of established foraging routines. Using ventrally attached time-depth recorders, we studied the individual foraging tactics of chick-rearing Crozet shags (Phalacrocorax melanogenis, Blyth 1860), as measured by the consistency in individual daily activity patterns and diving profiles over time. Individuals displayed a fidelity to the time of first daily trip to sea and also a strong fidelity to one, two or three depth ranges day after day. We suggest foraging area fidelity, a behaviour that could help increase foraging efficiency thanks to the memorization of the bottom’s topography and the habits of its fauna, as a hypothesis for explaining some of these patterns. We propose the question of foraging area fidelity should be more specifically addressed in the future.     

Diving behaviour of Adélie penguins (Pygoscelis adeliae) at Dumont D'Urville, Antarctica: nocturnal patterns of diving and rapid adaptations to changes in sea-ice condition

The diving behaviour of Adélie penguins (Pygoscelis adeliae) was studied with time-depth recorders at Dumont D'Urville, Antarctica, during the breeding seasons in 1995/1996 and 1996/1997. We studied penguins foraging at all breeding stages, in various sea-ice conditions. For the first time in this species we observed nocturnal patterns of diving as the penguins dived more frequently and spent more time underwater around midnight than around noon. This behaviour may be related to the abundance of neritic krill, Euphausia crystallorophias, in the diet. Dive depth and duration varied extensively over the cycle, and appeared related to sea ice conditions rather than representative of the locality (22 m/78 s and 40 m/102 s with and without sea-ice, respectively). Comparisons with other studies showed that different diving behaviour previously observed in different localities can also occur at the same locality, and in some cases over a single foraging trip of a single penguin when short-term variation of external conditions occurred. Accepted: 27 September 1999     

Interannual variation in the at‐sea behavior of California sea lions (Zalophus californianus)

To be successful, marine predators must alter their foraging behavior in response to changes in their environment. To understand the impact and severity of environmental change on a population it is necessary to first describe typical foraging patterns and identify the underlying variability that exists in foraging behavior. Therefore, we characterized the at‐sea behavior of adult female California sea lions (n = 32) over three years (2003, 2004, and 2005) using satellite transmitters and time‐depth recorders and examined how foraging behavior varied among years. In all years, sea lions traveled on average 84.7 ± 11.1 km from the rookery during foraging trips that were 3.2 ± 0.3 d. Sea lions spent 42.7% ± 1.9% of their time at sea diving and displayed short (2.2 ± 0.2 min), shallow dives (58.5 ± 8.5 m). Among individuals, there was significant variation in both dive behavior and movement patterns, which was found in all years. Among years, differences were found in trip durations, distances traveled, and some dive variables (e.g., dive duration and bottom time) as sea lions faced moderate variability in their foraging habitat (increased sea‐surface temperatures, decreased upwelling, and potential decreased prey abundance). The flexibility we found in the foraging behavior of California sea lions may be a mechanism to cope with environmental variability among years and could be linked to the continuing growth of sea lion populations.     

Foraging strategies and prey switching in the California sea otter

Summary Southern sea otters (Enhydra lutris nereis), in recovering from near extinction, are gradually extending their range to include areas from which they have been absent for more than one hundred years. This study took advantage of the otters' relatively sudden arrival in the area near Santa Cruz, California, to monitor their prey selection in the first two years of residence there. Foraging observations revealed that sea urchins (Strongly-locentrotus franciscanus) were heavily preyed upon initially, but virtually disappeared from the diet after one year of sea otter residence. The disappearance of sea urchins was accompanied by an increased use of kelp crabs (Pugettia producta) and the appearance of clams (Gari californica) in the otters' diet. Abalones (Haliotis rufescens) and cancer crabs (Cancer spp.) remained fairly stable as dietary items throughout the two year period. An electivity index was used to quantify sea otter preferences, which corresponded closely with a ranking scheme based on energy intake/unit foraging time calculated for each major prey species. As predicted by optimal foraging theory, sea otters prefer food species of high rank and replace depleted dietary items with those of next highest rank. The process of dietary switching was analyzed with respect to foraging success rates, and it appears that poor success rates, associated with predation on an increasingly rarer prey species (sea urchins), drive sea otters to hunt for different prey. Both patch selection and search image formation appear to function in this process. The potential effects on community structure and stability of predators exhibiting a preference for the most profitable prey are discussed.     

Summer activity pattern and Field Metabolic Rate of adult male sea otters (Enhydra lutris) in a soft sediment habitat in Alaska

Individual follows and instantaneous sampling were used to examine the behavior of adult male sea otters (Enhydra lutris) in Simpson Bay, Prince William Sound, Alaska, during the summer (May to August) of 2005 and 2006. Six behaviors (foraging, grooming, interacting with other otters, patrolling, resting, and swimming at the surface) were observed during four time periods (dawn, day, dusk, and night) to create 24-h activity budgets. Adult male sea otters were observed during 190 focal follows, representing 98 h of observation. Male otters allocated 27% of their time (over a 24-h period) to resting, 26% to swimming, 19% to grooming, 14% foraging, 9% to patrolling and 5% to interacting with other otters. Field Metabolic Rate (FMR) was estimated by combining the energetic costs for foraging, grooming, resting, and swimming behavior of captive otters from Yeates et al. (2007) with our activity budgets. Our study considered ‘patrolling’ to be energetically similar to ‘swimming’ and therefore the two categories were combined. This combined category accounted for the greatest percentage (43%) of energy expended each day followed by grooming (23%), resting (15%), feeding (13%) and other (5%). The estimated weight specific FMR for all activities was 686.7 kJ day^− 1 kg^− 1 and the total FMR was 19.04 MJ day^− 1. The FMR was 6.6 times the resting metabolic rate and 2.2 times greater than the allometric prediction for terrestrial mammals of similar size but similar to other marine mammals. With a peak summer sea otter density in 5.6 otters km^− 2, the low percentage of time spent foraging (even after correction for possible sampling biases) indicates that Simpson Bay is still below equilibrium density.     

DIVE DATA FROM SATELLITE TAGS AND TIME-DEPTH RECORDERS: A COMPARISON IN WEDDELL SEAL PUPS

The diving behavior of juvenile Weddell seals, Leptonychotes weddellii , was monitored simultaneously with time-depth recorders (TDRs) and satellitelinked time-depth recorders (SLTDRs). Recovered TDRs provided a complete record of the depth and duration of all dives, while data received from SLTDR tags via the ARGOS satellite system were compressed into the number of dives in each of six depth or duration bins. The dive information from the two types of tags was compared to determine if data compression, processing, and transmission influenced the data received.
While only half of the dive data collected by TDRs was also received from the SLTDR tags, the chance of receiving SLTDR data was independent of when diving occurred, when data was transmitted, and the subsequent dive activity. In addition, the number of dives in each depth and duration bin was an accurate representation of the actual dive behavior. Therefore, SLTDR tags were judged to provide data qualitatively similar to that provided by TDRs. The accuracy of seal locations provided by Service ARGOS was estimated by comparison to Global Positioning System (GPS) locations, and the average position error found to be significantly greater than predicted by Service ARGOS or reported in other studies (LCO locations ± 11.4 km, LC1 ± 5.0 km).     

Individual differences in foraging site fidelity are not related to time-activity budgets in Herring Gulls

Many populations consist of individuals that differ consistently in their foraging behaviour through resource or foraging site selection. Foraging site fidelity has been reported in several seabird species as a common phenomenon. It is considered especially beneficial in spatially and/or temporally predictable environments in which fidelity is thought to increase energy intake, thereby affecting time-energy budgets. However, the consequences for activity and energy budget have not been adequately tested. In this paper, we studied the consequences of fine-scale foraging site fidelity in adult Herring Gulls Larus argentatus in a highly predictable foraging environment with distinct foraging patches. We measured their time-activity budgets using GPS tracking and tri-axial acceleration measurements, which also made it possible to estimate energy expenditure. Individual variation in foraging site fidelity was high, some individuals spending most of their time on a single foraging patch and others spending the same amount of time in up to 21 patches. While time and activity budgets differed between individuals, we found no clear relationship with foraging site fidelity. We did find a relationship between the size of the birds and the level of site fidelity; faithful birds tend to have a larger body size. Although differences in foraging time and habitat use between individuals could play a role in the results of the current study, short-term consequences of variation in foraging site fidelity within a population remain elusive, even when focusing on individuals with a similar foraging specialization (Blue Mussels Mytilus edulis). Studying individuals over multiple years and under varying environmental conditions may provide better insight into the consequences and plasticity of foraging site fidelity.     

Recording the free-living behaviour of small-bodied, shallow-diving animals with data loggers

1. Time-depth data recorders (TDRs) have been widely used to explore the behaviour of relatively large, deep divers. However, little is known about the dive behaviour of small, shallow divers such as semi-aquatic mammals. 2. We used high-resolution TDRs to record the diving behaviour of American mink Mustela vison (weight of individuals 580-1275 g) in rivers in Oxfordshire (UK) between December 2005 and March 2006. 3. Dives to > 0.2 m were measured in all individuals (n = 6). Modal dive depth and duration were 0.3 m and 10 s, respectively, although dives up to 3 m and 60 s in duration were recorded. Dive duration increased with dive depth. 4. Temperature data recorded by TDRs covaried with diving behaviour: they were relatively cold (modal temperature 4-6 degrees C across individuals) when mink were diving and relatively warm (modal temperature 24-36 degrees C across individuals) when mink were not diving. 5. Individuals differed hugely in their use of rivers, reflecting foraging plasticity across both terrestrial and aquatic environments. For some individuals there was < 1 dive per day while for others there was > 100 dives per day. 6. We have shown it is now possible to record the diving behaviour of small free-living animals that only dive a few tens of centimetres, opening up the way for a new range of TDR studies on shallow diving species.     

Diving behaviour of dugongs, Dugong dugon

The diving behaviour of 15 dugongs (Dugong dugon) was documented using time-depth recorders (TDRs), which logged a total of 39,507 dives. The TDRs were deployed on dugongs caught at three study sites in northern Australia: Shark Bay, the Gulf of Carpentaria and Shoalwater Bay. The average time for which the dive data were collected per dugong was 10.4±1.1 (S.E.) days. Overall, these dugongs spent 47% of their daily activities within 1.5 m of the sea surface and 72% less than 3 m from the sea surface. Their mean maximum dive depth was 4.8±0.4 m (S.E.), mean dive duration was 2.7±0.17 min and the number of dives per hour averaged 11.8±1.2. The maximum dive depth recorded was 20.5 m; the maximum dive time in water >1.5 m deep was 12.3 min. The effects of dugong sex, location (study site), time of day and tidal cycle on diving rates (dives per hour), mean maximum dive depths, durations of dives, and time spent ≤1.5 m from the surface were investigated using weighted split-plot analysis of variance. The dugongs exhibited substantial interindividual variation in all dive parameters. The interaction between location and time of day was significant for diving rates, mean maximum dive depths and time spent within 1.5 m of the surface. In all these cases, there was substantial variation among individuals within locations among times of day. Thus, it was the variation among individuals that dominated all other effects. Dives were categorised into five types based on the shape of the time-depth profile. Of these, 67% of dives were interpreted as feeding dives (square and U-shaped), 8% as exploratory dives (V-shaped), 22% as travelling dives (shallow-erratic) and 3% as shallow resting dives. There was systematic variation in the distribution of dive types among the factors examined. Most of this variation was among individuals, but this differed across both time of day and tidal state. Not surprisingly, there was a positive relationship between dive duration and depth and a negative relationship between the number of dives per hour and the time spent within 1.5 m of the surface after a dive.     

Activity‐specific metabolic rates for diving,transiting, and resting at sea can be estimated from time–activity budgets in free‐ranging marine mammals

Time and energy are the two most important currencies in animal bioenergetics. How much time animals spend engaged in different activities with specific energetic costs ultimately defines their likelihood of surviving and successfully reproducing. However, it is extremely difficult to determine the energetic costs of independent activities for free‐ranging animals. In this study, we developed a new method to calculate activity‐specific metabolic rates, and applied it to female fur seals. We attached biologgers (that recorded GPS locations, depth profiles, and triaxial acceleration) to 12 northern (Callorhinus ursinus) and 13 Antarctic fur seals (Arctocephalus gazella), and used a hierarchical decision tree algorithm to determine time allocation between diving, transiting, resting, and performing slow movements at the surface (grooming, etc.). We concomitantly measured the total energy expenditure using the doubly‐labelled water method. We used a general least‐square model to establish the relationship between time–activity budgets and the total energy spent by each individual during their foraging trip to predict activity‐specific metabolic rates. Results show that both species allocated similar time to diving (~29%), transiting to and from their foraging grounds (~26–30%), and resting (~8–11%). However, Antarctic fur seals spent significantly more time grooming and moving slowly at the surface than northern fur seals (36% vs. 29%). Diving was the most expensive activity (~30 MJ/day if done non‐stop for 24 hr), followed by transiting at the surface (~21 MJ/day). Interestingly, metabolic rates were similar between species while on land or while slowly moving at the surface (~13 MJ/day). Overall, the average field metabolic rate was ~20 MJ/day (for all activities combined). The method we developed to calculate activity‐specific metabolic rates can be applied to terrestrial and marine species to determine the energetic costs of daily activities, as well as to predict the energetic consequences for animals forced to change their time allocations in response to environmental shifts.