title: Diving behaviour, dive cycles and aerobic dive limit in the platypus Ornithorhynchus anatinus.
abstract: We investigated the diving behaviour, the time allocation of the dive cycle and the behavioural aerobic dive limit (ADL) of platypuses (Ornithorhynchus anatinus) living at a sub-alpine Tasmanian lake. Individual platypuses were equipped with combined data logger-transmitter packages measuring dive depth. Mean dive duration was 31.3 s with 72% of all dives lasting between 18 and 40 s. Mean surface duration was 10.1 s. Mean dive depth was 1.28 m with a maximum of 8.77 m. Platypuses performed up to 1600 dives per foraging trip with a mean of 75 dives per hour. ADL was estimated by consideration of post-dive surface intervals vs. dive durations. Only 15% of all dives were found to exceed the estimated ADL of 40 s, indicating mainly aerobic diving in the species. Foraging platypuses followed a model of optimised recovery time, the optimal breathing theory. Total bottom duration or total foraging duration per day is proposed as a useful indicator of foraging efficiency and hence habitat quality in the species.
authors.affiliation: Anatomy and Physiology, University of Tasmania, Private Bag 24, Hobart, Tasmania 7001, Australia. philip@bethge.org
authors.forename: Philip
authors.initials: P
authors.lastname: Bethge
authors.forename: Sarah
authors.initials: S
authors.lastname: Munks
authors.forename: Helen
authors.initials: H
authors.lastname: Otley
authors.forename: Stewart
authors.initials: S
authors.lastname: Nicol
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D004242:Diving; D005260:Female; D008297:Male; D010101:Oxygen Consumption; D010987:Platypus / Q000235:genetics / Q000502:physiology*; D013550:Swimming; D013648:Tasmania; D013997:Time Factors