Data for: Sociality and signaling activity modulate information flow in river otter communication networks

Animal communication networks are built from interactions between senders
and receivers of signals. The drivers of signaling decisions, which are
the building blocks of such networks, are not well understood. Theory
predicts that conditions which ensure information spread to the largest
possible number of receivers should be favored. Several carnivores use
latrine sites for visual, olfactory and auditory signaling. We tested the
hypotheses that signaling behavior at latrine sites is influenced by
social structure and locally acquired information on the presence of
conspecifics, using coastal river otters (Lontra canadensis), in Alaska.
River otters exhibit a flexible social system of mostly males, that
communicate through scent marking at latrines. During scent marking, river
otters also perform feet stomping, which may add a visual component to
their signal. Using trail camera footage, we found that solitary otters
were more likely to perform both sniffing and scent marking compared to
otters in groups. Feet stomping was more intense for solitary otters, but
less pronounced during overmarking. Signalers demonstrated a greater
tendency to scent-mark when in smaller groups at highly active latrines,
whereas feet stomping was more intense in recently visited sites. When in
groups, scent-marking frequency increased when other individuals were
signaling, suggesting a positive feedback, possibly driven by feet
stomping. In concert, our results suggest that in river otters,
scent-marking decisions minimize signal dilution by being performed in
small groups and maximize the receivers through preferential signaling at
latrines with higher, more recent activity. Because signaling decisions in
social animals are linked to key life history events such as mating and
group membership shifts, understanding their individual and
population-level drivers can be crucial.