Animal sleep studies are about to leave the lab and enter the great outdoors. This follows the introduction to Australia by La Trobe University zoologists of the first miniaturised ‘sleep loggers’.
Black swans and tammar wallabies will be among the first animals in Australia to have their sleep documented in unprecedented detail – all in their natural habitat.
Head of the project is Dr John Lesku. His research paper ‘Sleep ecophysiology: integrating neuroscience and ecology’ has just been published in the international journal ‘Trends in Ecology and Evolution’ by Cell Press.
He said aspects of these species’ lifestyles make them interesting models for sleep studies, and particularly relevant to humans.
‘Male and female black swans, for example, take turns to incubate their eggs during the night or day, similar to humans working in shifts. Wallabies live under a night sky often associated with human light pollution. So we can try to answer questions such as: how does sleep change in these animals in the face of differing demands?’
Dr Lesku brought the ground-breaking technology to Australia from Switzerland’s University of Zurich (ETH Zurich), one of the world’s top science, engineering and technology universities.
In Germany, Dr Lesku was involved in pioneering work on ostriches and sandpipers. He helped record the latter’s brain activity during their short breeding season in the Arctic Circle.
In what sounds like good news for insomniacs, the study found sandpipers that slept the least, and remained active for more than 95 per cent of the time during their three-week breeding period, were the most attractive to females during mating season.
The new Australian work, on swans, wallabies and marsupial ‘mice’ called antechinus, is being carried out with Dr Kylie Robert and two PhD students, Anne Aulsebrook and Erika Zaid.
Other collaborators are Professor Raoul Mulder and Dr Therésa Jones at the University of Melbourne, and Dr Niels Rattenborg at the Max Planck Institute for Ornithology in Germany.
‘Sleep,’ said Dr Lesku, ‘influences every aspect of an animal’s health, well-being, even longevity. So to get really reliable information about exactly what sleep does, it needs to be studied in ecologically relevant settings.’
Until recently, few studies recorded sleep neurophysiology in the wild. ‘They had to be carried out in laboratories because electroencephalograms (EEG) needed large amplifiers, some the size of a small room.
‘In the last few years, these have dramatically reduced in size. They can now be used on animals weighing as little as 100g to study sleep in the wild,’ Dr Lesku said.
Not so slothful – and micro sleeps
This has led to a new discipline – sleep ecophysiology – and the formation of a new sleep ecophysiology group at La Trobe.
Dr Lesku said recent work in Europe found some species can be awake while exhibiting sleep behaviour.
‘In the three-toed sloth,’ he said, ‘colleagues found previous studies overestimated the amount of time they spent asleep.
‘On the other hand, birds were found to have hundreds of “microsleeps”, easily missed in behavioural studies.’
Habitat change and bird migration
Today, vast tracts of animal habitat and many important bird migration routes are affected by human development and climate change.
‘A comprehensive understanding of the links between sleep and fitness, conservation, the evolution of animal behaviour and how species cope with change has never been more important,’ Dr Lesku concludes.
‘We believe that the discipline of sleep ecophysiology, a nexus between neuroscience and evolutionary ecology, will offer crucial insights into the origins, evolution, functions, and modern-day importance of sleep – for humans as well as animals!’ he said.