Scent otter

Otters, L. lutra, scent mark with feces, called spraints in Britain. One study noted 12 times more frequent marking in winter when food is scarce than in summer. Spraints perhaps advertise depletion of patchy, recurrent resources to other otters and space out the animals. This non-competitive resource partitioning does not require agonistic reinforcement (Kruuk, 1992). Carnivores in general may heavily mark stable resource patches (Macdonald, 1980). 

Numbers of visits to scent stations baited with fatty acid tablets or prey odor such as shellfish oil allows estimation of population sizes of free-living red and gray foxes, raccoons, striped skunks, river otter, bobcats, cottontail rabbits, and oppossums. However, Smith et al. (1994) showed that the numbers of raccoon visits to scent stations did not reflect the size of their population. 

Gorman, M. L., Jenkins, D., and Cooper, R. J. (1978). The anal scent sacs of the otter [Lutra lutra). Journal of Zoology 186,463-474. 

Scent marking by otters Lutra lutra) signaling the use of resources. Behavioral Ecology 3,133-140. 

Castoreum or caster is a strongly scented creamy fluid derived from the genitals of male beavers. This name is also applied to similar materials taken from otters and muskrats. These fluids are used by the animals to mark their territories and to attract females. They are reputed to have the same effects on other species, notably humans, when incorporated into perfumes or creams. Castoreum perfume is produced by placing the entire gland into alcohol. 

We may find scent marks of the giant river otter. 

Within the chemical modality, conspicuousness of a signal increases by an expanding the active space or by placing it in the path of, and/or at the level of the sniffing animal, as in the hippopotamus. In contrast to the previous examples, no specially evolved visual or auditory components need be involved. For instance, beavers increase the active space of their scent marks by elevating them on mounds they construct from mud dug up from the bottom of their pond. Muskrats and river otter place their fecal marks at prominent spots along trails where encounters with conspecifics are likely. 

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