‘Live fast and die young’: Migratory animals are in decline because their fast-paced lifestyles mean they are less able to adapt to changing climates and habits, study claims
- Experts from the University of Exeter studied the ‘pace of life’ of 1,296 species
- They looked at metrics including longevity and the frequency of breeding
- The team found that migrants often grow faster, breed earlier and die younger
- Flying migrants are typically smaller than their static-living counterparts
- However, those migrating animals that swim or walk are often larger instead
Changing climates and habits pose a greater risk to migrating animals — especially those that fly — because they ‘live fast, die young’ and are thus less able to adapt.
Experts from Exeter studied nearly 1,300 mammal and bird species — finding that those who migrate typically grow faster, have offspring earlier and die younger.
The findings could help to explain why many migrant species appear to be declining, as they are less able to, for example, delay breeding conditions are poor.
They could also help to predict how migrating species may respond to environmental shifts in the future.
The team also noted that migrating animals that swim or walk are typically larger than their non-migrating equivalents, while flying migrants are usually smaller
Changing climates and habits pose a greater risk to migrating animals — especially those that fly — because they ‘live fast, die young’ and are thus less able to adapt. Pictured, a flock of fruit bats migrates across the sky as the sun begins to set
‘Many species migrate over long distances and this requires substantial amounts of energy,’ said paper author and conservation biologist Andrea Soriano-Redondo of the University of Exeter.
‘This energy cannot be used for other purposes such as self-maintenance or reproduction, so we would expect animals to adjust the amount of energy they use for these things,’ she added.
‘By prioritising reproduction over survival, “fast-living” species have the potential to increase numbers more rapidly — which may balance the long-term energy costs and short-term risks of migrating.’
In their study, Dr Soriano-Redondo and colleagues examined the so-called ‘pace of life’ of 1,296 species — looking at such metrics as longevity, the ages at which the female individuals reach sexual maturity and breeding frequencies.
‘We have long thought that migration is a risky behaviour,’ said paper author and animal ecologist Stuart Bearhop, also of the University of Exeter.
‘Animals often take a chance when they migrate, hoping to find the right conditions in their destination,’ he added.
‘In the case of birds that migrate to the High Arctic, they arrive in spring and have a short window in which to breed.’
‘Some will only attempt this if conditions are right — and if climate change degrades habitats, these “fast-living” species might miss their chance entirely.’
‘We have long thought that migration is a risky behaviour,’ said animal ecologist Stuart Bearhop of the University of Exeter. ‘Animals often take a chance when they migrate, hoping to find the right conditions in their destination,’ he added. Pictured, migrating geese
‘We think that walking and swimming migrants are generally larger because only large animals can store enough energy, and use it efficiently enough, to make long-distance land or sea migrations,’ added paper author and ecologist Dave Hodgson.
‘Among flying species, the opposite is true, as a large body mass makes flying more costly in terms of energy,’ he explained.
The full findings of the study were published in the journal Nature Communications.