Diving Physiology of the Platypus
The platypus obtains its food by foraging
on small invertebrates and plants on stream bottoms (Bethge 1997).
This makes diving a crucial element of its behavior.
Some characteristics of platypus
Platypi tend to have two types of dives: short, active, feeding dives
and longer, inactive dives. During inactive dives, the animals usually
rest on the stream bottom by wedging themselves under an object (Evans
et al., 1994).
Short, active dives average around a minute or less in length, whereas
longer, inactive dives can last up to 11 minutes, although the average
is closer to three minutes (Evans et al., 1994; Jones et al., 1987).
The ratio of dive:surface time can range from 2:1 to 20:1. Surprisingly,
there is no correlation between time spent diving and time spent at the
surface recovering (Jones et al., 1987). While feeding, platypi will
dive repeatedly over several hours (Bethge, 1997).
Top image courtesy of Healesville Sanctuary (http://www.zoo.org.au/,
bottom image courtesy of http://www.healthsci.utas.edu.au/physiol/mono/Mainpage.html
During all dives, heart rate decreases significantly (bradycardia).
This is generally thought to conserve oxygen stored in hemoglobin by decreasing
the rate of blood circulation to the tissues.
In short, active dives, heart rate is decreased but erratic. There
is significant post-dive tachycardia (increase in heart rate), possibly
to compensate for oxygen debt accumulated in the tissues.
In long, inactive dives, heart rate is lower and more stable. There
is no post-dive tachycardia (Evans et al., 1994).
What makes platypus
This page is a class assignment for Animal
Physiology at Davidson College.
For questions or comments, please email Will