no b, Sepu m L sed g s avi animal grows to maturity [1]. In contrast to terrestrial mammals, killer whale (Orcinus orca) and bottlenose dolphin (Tursiops are capable of sleeping during swimming and exhibiting slow wave activity in one hemisphere while the other hemisphere has been studied in only on...
| Other Authors: | |
|---|---|
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.539.4627 http://www.sleep.ru/lib/Lyamin_et_al_2007_Dolphin_behav_paper.pdf |
| Summary: | no b, Sepu m L sed g s avi animal grows to maturity [1]. In contrast to terrestrial mammals, killer whale (Orcinus orca) and bottlenose dolphin (Tursiops are capable of sleeping during swimming and exhibiting slow wave activity in one hemisphere while the other hemisphere has been studied in only one species — the pacific white-sided dolphin (Lagenorhynchus obliquidens, [14]). During slow captive bottlenose dolphins keep one eye open to avoid collisions with the pool wall. Although these hypotheses differ in minor details, they clearly emphasize the sentinel function of the asymmetrical eye state in sleeping dolphins and the ability of Physiology & Behavior 92 (2truncatus) neonates are highly active after birth, with their mothers not resting at the surface during the first 3 weeks postpartum [2,3]. This surface behavior is a common rest behavior in captive killer whales and dolphins [2–7]. Previous studies have noted a high level of activity in dolphin calves when compared to their mothers but did not examine this behavior in detail [8,9]. Terrestrial mammals have been shown to remain immobile during sleep with both eyes closed at all times. However, dolphins echelon swimming, when dolphins switched their positions, they also switched eye state in such a way, that the open eye was always directed toward their schoolmates. Similar, but limited, observations were also obtained from bottlenose dolphins [8,9]. Lilly [15] speculated that dolphins need to keep one eye open to scan their environment to avoid predation, while Goley [14] suggested that the open eye allows them tomaintain visual contact with group members. Sekiguchi and Kohshima [9] suggested thatcalves, the eye directed toward the mother was open more often (on average in 95 % of all observations in calf 1 and 99 % in calf 2) than the eye directed to the opposite side (82 % in calf 1 and 60 % in calf 2). Our data indicate that dolphin mothers and calves are highly active and vigilant during the initial period of the calf's life, ... |
|---|