Cricetidae

• One year later, and half a world away, debris began washing ashore on the west coast of North America.
• More than 280 Japanese coastal species such as mussels, barnacles and even some species of fish, had hitched a ride on the debris and made an incredible journey across the ocean.
• These species were still alive and had the potential to establish new populations.

The role of animal characteristics in dispersal

• For example, an invasive species can arrive in a new area and compete with native species for resources.
• They hypothesised there could be more general patterns in the animals that reach their destination successfully, related to certain characteristics.
• But despite a vigorous theoretical debate, the options to test these hypotheses were limited because such dispersal events are rare.
• These models allow us to estimate the movements of species’ ancestors while also considering their characteristics.

What we found

• This means that body size and life history are closely linked to how successful a species is at moving to and establishing itself in a new location.
• Animals with large bodies and fast life histories (breeding early and often, like water voles) generally dispersed more successfully, as expected.
• This means the combination of small body size and slow life history is very unlikely to be an advantage for dispersal across major barriers such as oceans.

It’s not just chance

• It is amazing to think that rare dispersal events, which can lead to the rise of many new species, are not completely random.
• Instead, the intrinsic characteristics of species can shape the histories of entire groups of animals, even though chance still may play an important role.