Cane toads and sea lions don’t have much in common, but they do have one big similarity: they’ve been on Earth a long time, and will probably be around quite a while longer.
That’s according to a new paper published in the journal BMC Evolutionary Biology. Researchers looked at 600 vertebrate species, assessing their geographic location, how they reproduced, body size, and color variation.
What they found was that these older species, like sea lions and cane toads, have survived on the planet for millions of years. These creatures have been tested in a wide range of environmental conditions, imparting them with greater resilience in the face of a changing climate. But younger species haven't been through such tests, which may leave them more vulnerable.
So what do these time-tested species have in common?
According to Story Hinckley at The Christian Science Monitor, color is important. Species are more successful if their patterns vary across different individuals and populations, such as owls and some lizards.
This variety of pattern allows the creatures to better blend into a range of environments and evade predators. According to a press release, species with at least two color morphs were on average 1.86 million years older than species that lack color variation.
The way a species gives birth was an important factor as well. It turns out that critters that give birth to live young were more resilient at all latitudes. But those that laid eggs, lasted longer at low latitudes—tropical areas surrounding the equator—than higher latitudes, where weather is much more variable. This means species that have live young are likely more able to adapt to changing weather and climate patterns than many amphibians, reptiles, and birds that lay eggs.
“Looking at the history of species survival will help us to predict which ones could be better able to deal with current climate change and to better predict the threat status of species on the red list of the International Union for Conservation of Nature,” one of the study authors Sylvain Dubey, a researcher at the University of Lausanne, says in the press release.
“The earlier we identify and protect species in trouble, the more likely they survive and recover,” Noah Greenwald, Endangered Species Director at the Center for Biological Diversity, tells Hinckley. “We need to know the species to watch so if we see a decline, maybe we can take early action.”