New research has revealed that newborn deer fawns differ both in sleeping patterns and the rate of development from birth on an individual basis, as we see in newborn human babies, in the first study of its kind by Queen’s University Belfast (QUB).
The researchers recorded the sleeping behaviour of free-ranging fallow deer fawns during the first five weeks of life at Phoenix Park in Dublin.
They used minimally-invasive biologging technology, developed by WildBytes and the Swansea Laboratory of Animal Movement at Swansea University, to track the animals while they remained hidden in the woods and vegetation, isolated from their mothers and wider herd.
This study shows the marked and consistent individual differences among deer in sleep quantity, quality and fragmentation, as well as the rate sleep develops – in the first week of life, the shortest sleeping fawn slept about half the time of the longest sleeping fawn.
Newborn deer
The study has been led by Queen’s University Belfast in collaboration with researchers at Swansea University, and supported by University College Dublin (UCD).
It was supported through a Department for the Economy PhD studentship via Queen’s and the Association for the Study of Animal Behaviour (ASAB).
Reader at QUB, Dr. Isabella Capellini said: “This is the first study of its kind which has looked at the sleeping habits of newborn species in the wild and has shown fallow deer fawns’ sleep rapidly decreases and consolidates in the first five weeks of life.
“Our results suggest that differences between fawns may have important implications for the fawns’ future health and might reflect pace-of-life syndromes, that is how individuals invest in growth, reproduction and health over their lifetime.”
The research also looked at the conditions affecting the sleeping behaviour of fawns and found sleep time was reduced and was of lower quality on warmer days and further compromised in more humid conditions, but was higher on days with greater rainfall.
Prof. Luca Börger from Swansea University added: “Understanding the ecology of sleep of wild animals is a fascinating and crucially important topic, but we virtually do not know anything about it, due to difficulties in recording sleep non-invasively in free-living animals.
“We show how animal-borne accelerometers (sensors similar to Fitbits), if coupled with dedicated software methods to analyse the data, allow us to investigate sleep in the wild for the first time.”
