Social organization of otters in relation to their ecology

Abstract

Otter species are known to fluctuate intraspecifically from a solitary lifestyle to group-living arrangements. By examining what is known about habitat use and foraging style in otters of 13 different species, based on 93 studied sites, we assessed (1) the relationship between social habits and preferred habitats, (2) the relationship between species and prey preferences, and (3) the effect of predator avoidance on their social organization in order to assess the socio-ecological factors influencing otters. Females remain the core of their social stability. We show the major influence of habitats and feeding strategies (i.e. socio-ecology) of otters. The different species of solitary otters most often inhabit linear environments, such as freshwater ecosystems or wave-exposed marine coasts, and their habitat is often subject to disturbances that fragment their functional continuity. Social otters are more often found in extensive habitats with high plant cover, regular food resources and in areas with large predators compared to solitary species. The maintenance of regular resources and the fact that the main trophic resources are replenished rapidly might be determining factors driving sociality. Group-living and bachelor congregations among otters can also respond to pressure from large predators. This suggests that foraging, habitat use and the presence of large predators may be the drivers of sociality in otters. We conclude that most otters have a greater social potential than previously assumed, which is confirmed by their various vocalizations recently described.

Human disturbances and the daytime activity of sympatric otters along equatorial Amazonian rivers

“…As far as we are aware there have been no reports of direct interspecific competition between any otter species. Indeed, sympatry facilitated by habitat, trophic and temporal separation has been widely documented between otter species across the globe, with sympatry in up to three otter species found in Thailand ( Ebensperger & Botto-Mahan, 1997 ; Krupa, Borker & Gopal, 2017 ; Kruuk et al, 1994 ; Lélias, Lemasson & Lodé, 2021 ; Somers & Purves, 1996 ). We found giant and neotropical otters were on average approximately 12 km and 3 h apart when detected on the same day, which indicates that competition is avoided both temporally and spatially.…”

Low signs of territorial behavior in the Eurasian otter during low-water conditions in a Mediterranean river

“…In general, these studies agreed on the relatively low density of Eurasian otter populations compared to those reported for terrestrial mesocarnivores 21 , 22 but this is also dependent on habitat specialization. Although the otter is generally considered to be a solitary territorial species 11 , 23 , a recent meta-analysis 24 showed that in certain situations of high vegetation cover and prey availability, otter populations can exhibit other social patterns, including flexible territoriality and matrilineal groups. Quaglietta et al 25 found such patterns in southern Portugal, with some plasticity in social behavior.…”

Agonism between family groups of cooperative breeding smooth-coated otters (Lutrogale perspicillata)

“…Of 13 extant species of otters ( Lutrinae ), several are social (Lodé et al, 2021), and at least three are cooperative breeders: giant ( Pteronura brasiliensis ), small-clawed ( Aonyx cinereus ), and smooth-coated ( Lutrogale perspicillata ) otters (Bungum et al, 2021; Lélias et al, 2021). Smooth-coated otters typically live in family groups (“romps”) that consist of a breeding pair and their offspring of different ages (Bungum et al, 2021).…”