alt.image_decorative

publications.titre

Breaking the fast: First report of dives and ingestions events
in molting Southern elephant seals

Southern elephant seals experience a “catastrophic molt”, an energetically costly physiological event characterized by the total renewal of hair and epidermis and that requires a high peripheral vascular circulation. Molting individuals are therefore constrained by high metabolic heat loss. Molting animals have an extended period of fasting and in this species the molt period was previously thought to be spent entirely on land.

We therefore investigated movement-patterns and stomach temperature of female Southern elephant seals during the molting period. In contrast to previous predictions, our data demonstrated for the first time that molting females, conversely to what has been hypothesized, do travel at sea, and ingest water and/or prey items, despite the cost of cold exposure during their critical molt period.

We conclude that the paradigm of exclusive fasting during the molt in this species should be reconsidered as well as the possible fitness consequences of this behavior.

publications.article.infos

Avis du CNR BEA relatif au bien-être des carnivores domestiques (chiens et chats)
en contexte d’évènements

Le CNR BEA a été sollicité par la DGAL le 14 septembre 2020 dans le but de définir un délai de repos minimum pour les carnivores domestiques entre deux manifestations type exposition-ventes.

Après avoir étudié la bibliographie existante et échangé avec des experts du domaine, le CNR BEA a proposé de faire évoluer la sollicitation vers un travail permettant un premier état des lieux du bien-être des carnivores domestiques lors d’évènements de rassemblements (expositions, concours, salons, ventes) en France, hors contexte sanitaire dû à la Covid-19.

publications.article.infos

Effects of a new dietary supplement on behavioural responses
of dogs exposed to mild stressors

The effectiveness of a new dietary supplement (derived from fish hydrolysate and melon juice concentrate rich in superoxide dismutase) in reducing fear and stress-related behaviours in pet dogs was examined in a double-blind, placebo-controlled, randomized study.

39 dogs were recruited after the owners had filled out a fear susceptibility index questionnaire. Over a 30-day period, one group of dogs received the supplement, and another group a placebo.

Twelve behavioural variables were recorded in a series of four subtests (ST1-ST4) on days 0, 15 and 30. Saliva cortisol levels were measured before and after each set of STs.

The dogs rated as more fearful displayed significantly higher cortisol values before the day 0 test session, were less active, spent less time playing with the experimenter, and approached the unfamiliar object less frequently. The owners did not correctly guess whether their dog had received the supplement or not. Behaviours of dogs were significantly different across the three sessions, with significant increases of stress-related behaviours (time spent in the door zone, number of interactions with the door, of whining, and of lip-licking). Conversely time spent with the experimenter increased, interactions and curiosity for the novel object and play with the experimenter decreased, presumably due to a habituation process. This suggests that the design of the four subtests session was relevant to test for mild stressors situations. Moreover, supplemented and placebo dogs responded differently to the three test sessions, indicating a supplement effect on dogs' behaviours and their adaptation to mild stressors situations.

The trial results suggested that the supplement facilitates activity and curiosity in a familiar environment, promotes dog-human interactions with an increased human familiarity, and tends to reduce subtle stress behaviours. Our results suggest that the supplement was effective in the context of mild stressors and habituation.

publications.article.infos

Metabolic heat loss in southern elephant seals (Mirounga leonina)
differs with stage of moult and between habitats

The moult in southern elephant seals (Mirounga leonina) represents an especially energetically demanding period during which seals must maintain high skin temperature to facilitate complete replacement of body fur and upper dermis. In this study, heat flux from the body surface was measured on 18 moulting southern elephant seals to estimate metabolic heat loss in three different habitats (beach, wallow and vegetation). Temperature data loggers were also deployed on 10 southern elephant seals to monitor skin surface temperature. On average, heat loss of animals on the beach was greater than in wallows or vegetation, and greater in wallows than in vegetation. Heat loss across all habitats during the moult equated to 1.8 x resting metabolic rate (RMR). The greatest heat loss of animals was recorded in the beach habitat during the late moult, that represented 2.3 x RMR. Mass loss was 3.6 ± 0.3 kg day-1, resulting in changes in body condition as the moult progressed. As body condition declined, skin surface temperature also decreased, suggesting that as animals approached the end of the moult blood flow to the skin surface was no longer required for hair growth.

publications.article.infos

Environmental and physiological determinants of huddling behavior of
molting female southern elephant seals (Mirounga leonina)

While endotherms can rely on their insulation to reduce heat loss to adapt to cold environments, renewing of fur during molt impairs insulation while they have to perfuse the periphery to support epidermal tissues. The southern elephant seal Mirounga leonina undertakes an annual catastrophic molt while fasting on land in a wet, windy and cold environment. However, southern elephant seals show characteristic aggregation patterns that are predicted to reduce high metabolic costs during the molt. Between 2012 and 2016, 59 female elephant seals were tracked on land during their molt to study their aggregation behavior in relation to molt stage, habitat type and local weather conditions. Infrared thermography and stomach temperature loggers were used to observe variation in body surface and internal temperature in relation to molt stage and aggregation behavior. We found that thermal constraints varied during the molt, with a peak in surface temperature during the mid-stage of the molt. Wallows (mud pools) appear as favorable habitat to aggregate while molting. Indeed, wallows offered a warmer microclimate with greater ground temperature and lower wind speed. Moreover, there was a greater proportion of aggregated seals and larger group size in wallows. These aggregation patterns in wallows were influenced by local weather such that a greater proportion of seals were located in the center of the aggregation, and larger group size occurred during days of unfavorable meteorological conditions. We also observed a higher proportion of seals at mid-stage of molt amongst aggregated seals compared to isolated individuals. This aggregation behavior may reduce the cost of thermogenesis as surface body temperature and stomach temperature were cooler by 1.0 °C and 1.5 °C, respectively, in aggregated compared to isolated seals. As a consequence, huddling behavior may be thermally advantageous for female southern elephant seals during the molt.

publications.article.infos

Local weather and body condition influence habitat use and movements on land
of molting female southern elephant seals (Mirounga leonina)

Southern elephant seals (Mirounga leonina) are known to move and aggregate while molting, but little is known about their behavior on land during this time. In this study, 60 adult females were monitored (23 with GPS tags) during four molting seasons, between 2012 and 2016 at Kerguelen Archipelago, Indian Ocean. Population surveys were recorded each year (N = 230 daily counts), and habitat use was analyzed in relation to the stage of the molt and local weather. Based on stage of molt, habitat use, and movements on land, we classified the molt of elephant seals into three phases: (1) a “search phase” at the initial stage of molt when grass and wallow habitats were used and characterized by greater mean distances travelled on land per day compared with the two other phases; (2) a “resident phase”: during initial and mid-stage of molt when animals were found in grass and wallow habitats but with less distance moved on land; and (3) a “termination phase” at the final stage of molt where grass and beach habitats were occupied with no change in distances. Windchill and solar radiation influenced individual distances moved per day (mean 590 ± 237.0 m) at the mid- and final stage of molt such that animals travelled greater distances on days of low windchill or high solar radiation. Individual variation in distance moved and relative habitat use were also linked to body mass index (BMI) at arrival on the colony, as females with higher BMI moved less and preferred beach habitat. Moreover, the individual rate of molt increased with the use of wallows. Aggregation rate tended to be negatively correlated with distances moved. We therefore suggest that individuals face an energetic trade-off while molting, balancing energy expenditure between movement and thermoregulation.

publications.article.infos

Implantation of subcutaneous heart rate data loggers
in southern elephant seals (Mirounga leonina)

Unlike most phocid species (Phocidae), Mirounga leonina (southern elephant seals) experience a catastrophic moult where they not only replace their hair but also their epidermis when ashore for approximately 1 month. Few studies have investigated behavioural and physiological adaptations of southern elephant seals during the moult fast, a particularly energetically costly life cycle’s phase. Recording heart rate is a reliable technique for estimating energy expenditure in the field. For the first time, subcutaneous heart rate data loggers were successfully implanted during the moult in two free-ranging southern elephant seals over 3–6 days. No substantial postoperative complications were encountered and consistent heart rate data were obtained. This promising surgical technique opens new opportunities for monitoring heart rate in phocid seals.

publications.article.infos

Impact of specific executive functions on driving performance in people with Parkinson's disease

Executive functions encompass various cognitive processes and are critical in novel or demanding driving situations. Our aim was to determine the role of impairments in specific executive functions (updating, flexibility, inhibition) on road performance in drivers with Parkinson's disease (PD), a condition commonly associated with early executive dysfunction. In this pilot study, 19 patients with mild to moderate PD and 21 healthy controls matched for age, education, and driving experience were tested using a neuropsychological battery assessing global cognitive abilities, updating (n-back task), flexibility (plus-minus task), and inhibition (Stroop test). Participants also underwent a 45-minute road test in which they were scored by a driving instructor and a second experimenter. To separate “at-risk” drivers from safe drivers, a composite driving indicator was calculated from the Test Ride for Investigating Practical Fitness to Drive score, the penalty score from the observation grid, and the number of safety interventions made by the driving instructor. Eight of the 40 drivers (all PD) were rated as “at risk.” Measures of updating (the n-back task) and mental flexibility (the plus-minus task) predicted driving safety even after adjustment for group status, explaining 53% of the total variance. These 2 tests also discriminated between safe and “at-risk” drivers within the PD group. These findings, although preliminary, suggest that updating and mental flexibility are critical for safe driving in PD. Assessment batteries for driving fitness should probe different aspects of executive functions, specifically when evaluating drivers with PD. © 2013 International Parkinson and Movement Disorder Society

publications.article.infos