We investigated seasonal changes in haematology and blood viscosity in free-ranging echidnas, Tachyglossus aculeatus (37 females, 28 males, and 17 juveniles), some of which had been fitted with radio transmitters, allowing them to be located and bled during hibernation. Only one haematological parameter, mean cell haemoglobin concentration, appeared to show any clear relationship with hibernation. Seasonal variation was most marked in females, with red-cell count, haematocrit, and haemoglobin levels highest in summer and lowest in spring (P < 0.001). Males had higher values than females or juveniles (P < 0.05). Plasma osmolality was highest in summer (307 ± 4 mosmol/kg, n = 11) and lowest in autumn (290 ± 6 mosmol/kg, n = 6). Contrary to expectation, blood from hibernating echidnas, when measured at 32°C and at a haematocrit of 45%, showed significantly higher viscosity than blood from nonhibernating echidnas. These increases in mean cell haemoglobin concentration and blood viscosity during hibernation appear to be due to a build-up of senescent red cells and a reduced rate of erythropoiesis.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Physiology
Research Field:	Comparative Physiology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Environmental Sciences
UTAS Author:	Andersen, NA (Dr Niels Andersen)
UTAS Author:	Lovell, D (Mr David Lovell)
UTAS Author:	Nicol, SC (Associate Professor Stewart Nicol)
ID Code:	20060
Year Published:	2000
Web of Science® Times Cited:	5
Deposited By:	Anatomy and Physiology
Deposited On:	2000-08-01
Last Modified:	2011-08-04
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