Visual timing abilities of a harbour seal (Phoca vitulina) and a South African fur seal (Arctocephalus pusillus pusillus) for sub- and supra-second time intervals

Abstract

Timing is an essential parameter influencing many behaviours. A previous study demonstrated a high sensitivity of a phocid, the harbour seal (Phoca vitulina), in discriminating time intervals. In the present study, we compared the harbour seal's timing abilities with the timing abilities of an otariid, the South African fur seal (Arctocephalus pusillus pusillus). This comparison seemed essential as phocids and otariids differ in many respects and might, thus, also differ regarding their timing abilities. We determined time difference thresholds for sub-and suprasecond time intervals marked by a white circle on a black background displayed for a specific time interval on a monitor using a staircase method. Contrary to our expectation, the timing abilities of the fur seal and the harbour seal were comparable. Over a broad range of time intervals, 0.8-7 s in the fur seal and 0.8-30 s in the harbour seal, the difference thresholds followed Weber's law. In this range, both animals could discriminate time intervals differing only by 12 % and 14 % on average. Timing might, thus be a fundamental cue for pinnipeds in general to be used in various contexts, thereby complementing information provided by classical sensory systems. Future studies will help to clarify if timing is indeed involved in foraging decisions or the estimation of travel speed or distance.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Distance Estimation in Reproduction Tasks in a Harbor Seal (Phoca vitulina)

“…Second, the seal's performance was highest if it was reproducing a distance with a specific swimming speed. As previously it was documented that harbor seals have an accurate sense of time [54,55], the seal might have kept swimming speed constant, allowing it to use time as a measure for distance. Future studies are required to further elucidate the mechanism of distance estimation in harbor seals.…”

Can harbor seals (Phoca vitulina) discriminate familiar conspecific calls after long periods of separation?

“…Alternative explanations for the absence of effect could be that our experiment was underpowered or not well-enough targeted to this species’ ecology. Harbor seals are subject of increasing scientific work; empirical evidence on vocal learning, sound production, time perception, hearing, auditory memory, and social dynamics, to name a few, is growing ( Heinrich, Dehnhardt & Hanke, 2016 ; Ravignani et al, 2016 ; Kastelein, Helder-Hoek & Terhune, 2018 ; Wilson et al, 2018 ; Adams et al, 2020 ; Galatius et al, 2020 ; Heinrich, Ravignani & Hanke, 2020 ; Borda et al, 2021 ). Once a clearer socioecological picture is available, we hope that our experiment will be modified to properly target the threshold of long-term memory capacities in harbor seals.…”

Peer Review #1 of "Can harbor seals (Phoca vitulina) discriminate familiar conspecific calls after long periods of separation? (v0.1)"

“…Alternative explanations for the absence of effect could be that our experiment was underpowered or not well-enough targeted to this species' ecology. Harbor seals are subject of increasing scientific work; empirical evidence on vocal learning, sound production, time perception, hearing, auditory memory, and social dynamics, to name a few, is growing (Heinrich et al 2016;Ravignani et al 2016;Kastelein et al 2018;Wilson et al 2018;Adams et al 2020;Galatius et al 2020;Heinrich et al 2020;Torres Borda et al, 2021). Once a clearer socioecological picture is available, we hope that our experiment will be modified to properly target the threshold of long-term memory capacities in harbor seals.…”