Seasonal, diel, and ontogenetic patterns of within-den behavior in beavers (Castor canadensis)

Abstract

a b s t r a c tDespite the ubiquity of denning as a natural history strategy among terrestrial vertebrates, little is known regarding basic patterns of within-den behavior, how such patterns are influenced by demographic and environmental parameters, or how within-den behavioral repertoires relate to activities performed in external environments. Den usage is believed to facilitate increased expression of behaviors that compromise fitness in external environments, though empirical data validating these assumptions are generally lacking. Relative isolation from external light cues within dens has been linked to temporal patterns of den use, yet few studies examine associations between photoperiod and rhythmicity strictly for within-den behavior. Also, for denning species with relatively equivalent parental investment, conclusions regarding sex-specific behavior have been equivocal, and no studies have examined potential segregation of parental activity within dens. We videorecorded 1506 h of within-den activity from 23 beaver (Castor canadensis) colonies and characterized behavioral patterns based on sex and age over daily and monthly intervals. Within-den time-activity budgets were equivalent among male and female adult beavers, with feeding, sleeping, allogrooming, and individual grooming accounting for more than 95% of all recorded behaviors. Behavioral repertoires within dens exhibited distinct seasonality and were influenced by temporal variation in external conditions associated with food availability, indicating linkages between activities within and outside of dens. Lastly, beaver age classes varied considerably in their associations between diel activity patterns and photoperiod, with adults and kits exhibiting single and multiple sleep-wake cycles, respectively.

Causes and consequences of inverse density‐dependent territorial behaviour and aggression in a monogamous mammal

“…We found no evidence for intra‐territorial disputes among beavers within the same family group, as the probability of obtaining a tail scar was independent of family size. This is in line with other studies from North American beavers (Baker & Hill, ; Crawford, Bluett, & Schauber, ; Mott, Bloomquist, & Nielsen, ). Older territory owners had comparatively more tail scars, which could be a result of senescence (discussed in detail in Mayer, Künzel, et al, ), as suggested for other species (Hu & Morse, ; Piper et al, ).…”

Movement characteristics of American beavers (Castor canadensis)

“…We monitored radio-tagged beavers at least two times per week from 9 May 2011 to 27 July 2011 and bi-weekly from 19 August 2011 to 20 April 2012. We systematically varied the order in which we tracked beavers in each wetland and the time of night of radio tracking for each beaver across all tracking occasions to ensure that the temporal distribution of estimated locations was unbiased over the beavers' most active periods between 17:00 and 08:00 h (Mott et al, 2011). We only considered beavers having 20 locations with location estimates of 95% error ellipse < 0.5 ha throughout the study period for annual home-range estimation (N = 26 beavers).…”

Conspecific Aggression by Beavers (Castor canadensis) in the Sangamon River Basin in Central Illinois: Correlates with Habitat, Age, Sex and Season

“…Sun (2003) 35 speculated that intercolony agonistic encounters were rare, but noted a lack of empirical evidence 36 to support these views. Bradt (1938) suggested that subadults were actively driven from the 37 colony by adults, but videos of beavers in dens have revealed few agonistic behaviors among 38 colony members (0.1% of time-activity budget; Mott et al, 2011). Behaviors of beavers 39 engaged in agonistic encounters (e.g., pushing, lunging, sham-biting and biting; Bradt, 1938; 40 Wilsson, 1971; Hodgdon, 1978;Hodgdon and Lancia, 1983) Behavioral adaptations also should reduce the incidence and severity of injuries caused by 47 conspecific aggression.…”