The big sleep
HORSES DON’T REQUIRE as much sleep as humans and so they end up being far more active through the hours of darkness.
“Horses will graze, move and socially interact at night,” says behaviourist Rosa Verwijs. “They have more rods than cones in their retina, and also a tapetum lucidum, meaning that they can see better at night or in dim light than humans.”
Research has demonstrated that horses are able to discriminate between objects in nearly complete darkness, and certainly in much darker conditions than humans can, meaning that they can also negotiate uneven terrain at night. They are highly vigilant prey animals and they have good enough eyesight to continue normal activities, such as eating in dark stables and foraging in fields, on moonless nights.
“They may not be able to see fine detail in such dark conditions, but are unlikely to trip or walk into inanimate objects as they can see these well enough,” says Rosa.
The light/dark cycle affects many physiological functions in horses mainly through hormonal mechanisms, and
