Behavior in Free-Living American Black Bear Dens: Parturition, Maternal Care, and Cub Behavior

Rogers, Laura M.; McColley, Linda; Dalton, Janet; Stroner, Jim; Hajicek, D.R.; Partin, Adam; Burghardt, Gordon M.

doi:10.3390/ani10071123

Cited by 6 publications

(3 citation statements)

References 36 publications

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“…As described above, we used a quantitative metabolic marker (fecal output) to align all cycles. Other bear studies have similarly used alternative non-invasively obtained, non-endocrine markers (for example temperature and activity data) to estimate implantation and birth date during hibernation [36, 37].…”

Section: Resultsmentioning

confidence: 99%

Evolutionary survival strategies of the female giant panda: optimizing energy resources and expenditure prior to pregnancy by postponing corpus luteum reactivation

Wauters

Wilson

Bouts³

et al. 2022

Preprint

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The giant panda reproductive physiology shows important similarities with at least six of the eight existing bear species: the occurrence of diapause and/or pseudopregnancy is commonly described in bears. Nevertheless, significant differences including the earlier breeding season with - in general - a single estrus, a shorter delay of implantation and a more variable birth season, indicate an evolutionary adaptation from the seasonal reproductive traits described in hibernating bear species. In this study we aimed to determine true pregnancy length for giant pandas and to open the discussion on the peculiarities of giant panda reproductive biology, more specifically focusing on the rationale behind their short-seasoned reproductive cycle compared to the other bear species. For this purpose, metabolic (body weight and fecal output) profiles were matched with endocrine changes, mainly urinary progesterone metabolites, in 5 pregnant, 8 non-birth and 6 pseudopregnant cycles of 6 female giant pandas. Pregnancy in giant pandas lasts only 42 days from early reactivation of the corpora lutea (CLs) until birth. In addition, our findings urged the need to redefine the generally accepted biphasic progesterone profile into a triphasic primary progesterone rise (corpus luteum dormancy (CLD) I, II and III) prior to entering the active luteal phase (= secondary progesterone rise). Two episodes of progesterone increase (CLDII: 81.20 ± 5.85 days versus CLDIII: 60.80 ± 3.83 days prior to birth for pregnant cycles) were identified, respectively corresponding to CL reactivation (74-88 days prior to birth) and implantation ( ± 60 days prior to birth) in other bear species. The progesterone concentration during CLDIII was higher in pregnant cycles, indicating a potential communication between maternal tissues and blastocyst(s) enhancing progesterone concentrations and thus allowing optimal priming of uterine tissues to better prepare for blastocyst reactivation/development. Compared with other bear species, giant pandas seem to shorten the active luteal phase, and thus pregnancy, by approximately 30 days by actively postponing CL reactivation. Potential mechanisms in play overruling and suppressing the evolutionary conserved photoperiodical triggers of CL reactivation are discussed while a parallel study will further elaborate on the CL dynamics during giant panda gestation.

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Section: Resultsmentioning

confidence: 99%

Evolutionary survival strategies of the female giant panda: optimizing energy resources and expenditure prior to pregnancy by postponing corpus luteum reactivation

Wauters

Wilson

Bouts³

et al. 2022

Preprint

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show abstract

“…To explore the motor training hypothesis, further steps in the study of spotted hyena object play are required. It would be important to trace the development of this activity covering the period from lactating to food independence and evaluate if the beginning of the independent phase coincides with the decrease of object play as suggested by Rogers et al (2020).…”

Section: Discussionmentioning

confidence: 99%

Play fighting in wild spotted hyaenas: like a bridge over the troubled water of a hierarchical society

2021

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“…Similarly, activity data has been used to determine parturition dates in the Scandinavian brown bear, with reduced activity levels reported during the postpartum period (Friebe et al, 2014). Furthermore, Rogers et al (2020) reported increased movements during the labor and reduced movements after delivery using cameras placed inside the den of freeranging female American black bears (Ursus americanus). Taken together, these observations provide a characteristic activity pattern that could facilitate the determination of parturition in free-ranging populations.…”

Section: Introductionmentioning

confidence: 99%

Extrinsic and intrinsic factors drive the timing of gestation and reproductive success of Scandinavian brown bears

et al. 2022

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IntroductionClimate change is altering the reproductive phenology of many organisms, but the factors that influence the timing of gestation in ursids are still poorly understood. Higher temperatures in spring are already causing an earlier den exit in some brown bear populations, and a temporal mismatch between hibernation and reproduction could have dramatic consequences for reproductive success. Therefore, understanding the factors that control the timing of these events is important to forecast the consequences of climate change on population growth rates.MethodsIn this study, we used abdominal temperature loggers and GPS collars with acceleration sensors on 23 free-ranging pregnant female brown bears living in two areas in Sweden (61°N and 67°N latitude) to pinpoint hibernation and reproductive events. We investigated how intrinsic and extrinsic factors influence the termination of embryonic diapause and parturition, as well as their impact on reproductive success.ResultsThe termination of embryonic diapause was later in the northern area compared to the southern area and occurred earlier when ambient temperature at den entry was higher in both areas. In the southern area, young adults (i.e., females = 7 years old) had a delayed parturition when bilberry abundance was low the year of mating. Additionally, young adults had a lower reproductive success than adults and their probability to reproduce successfully was dependent on bilberry abundance, whereas adult females were not affected by this parameter.DiscussionAs den exit occurs later in the northern study area, we suggest that a later parturition might ensure that females lactate their cubs in the den for a reasonable amount of time while fasting. Similarly, a later parturition combined with an earlier emergence could allow young adults to spend less time in the den lactating if they could not reach an optimal body condition prior to hibernation. But as a result, their cubs are younger and more vulnerable when they leave the den leading to lower survival rates. Our results suggest that a decreased berry abundance in the fall could impact the reproductive and hibernation phenology of Scandinavian brown bear females and lead to a lower cub survival with potential consequences on the population dynamics.

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Behavior in Free-Living American Black Bear Dens: Parturition, Maternal Care, and Cub Behavior

Cited by 6 publications

References 36 publications

Evolutionary survival strategies of the female giant panda: optimizing energy resources and expenditure prior to pregnancy by postponing corpus luteum reactivation

Evolutionary survival strategies of the female giant panda: optimizing energy resources and expenditure prior to pregnancy by postponing corpus luteum reactivation

Play fighting in wild spotted hyaenas: like a bridge over the troubled water of a hierarchical society

Extrinsic and intrinsic factors drive the timing of gestation and reproductive success of Scandinavian brown bears

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