Earliest mammals had night vision

New genetic evidence confirms a long-held hypothesis that our earliest mammalian ancestors indeed had powerful night vision.

The findings published in the journal Scientific Reports says that adapting to life in the dark helped the early mammals find food and avoid reptilian predators that hunted by day.

The research team examined genes involved in night vision in animals throughout the evolutionary tree, looking for places where those genes became enhanced.

“This method is like using the genome as a fossil record, and with it we’ve shown when genes involved in night vision appear,” explained lead researcher Liz Hadly, Professor of Biology at Stanford University. Mammals and reptiles share a common ancestor, with the earliest mammal-like animals appearing in the Late Triassic about 200 million years ago.

Fossil evidence suggests that early mammals had excellent hearing and sense of smell and were likely warm-blooded.

The team members examined night vision genes in many mammals and reptiles, including snakes, alligators, mice, platypuses and humans.

From this, they deduced that the earliest common ancestor did not have good night vision and was instead active during the day. However, soon after the split, mammals began enhancing their night vision genes, allowing them to begin to roam at night.

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