The lioness grew increasingly thin since she was constantly guarding her young and not hunting. But her natural instincts did apparently kick in when one of the young oryxes she had adopted died naturally in the night -- and she ate it.
Some wildlife experts tried to explain the behavior by saying perhaps the lioness couldn't have her own cubs and thus sought out the mothering role. Others suggested she may have had a mental disorder.
Barash chalks it up to chance.
"Imprinting doesn't only occur when a baby attaches to a parent," he said. "The mother will imprint on the baby as well. Maybe the lioness was exposed to an oryx at a critical time."
Barash recounted another case where a sparrow started feeding a large goldfish. The goldfish would swim to the edge of its pond and hold its mouth open, whereupon the sparrow would deposit its catch of the day.
"It was a happy coincidence for the fish," he said.
Sometimes happy coincidence leads to odd romance. In 1986, thousands of people flocked to Shrewsbury, Vt., to observe the apparent liaison between Jessica, a Hereford cow, and a huge male moose dubbed Bullwinkle. For 76 days, the moose never left Jessica's side and the two were often observed nuzzling affectionately.
More recently, a yearling moose and a 20-year-old horse became close pals last summer at a farm outside Groton village in Vermont.
Some might be inclined to regard such pairings as romantic and convention-defying -- like Romeo and Juliet or the Duke and Duchess of Windsor. But biologists like Barash see the quirky matchups -- and love, in general -- through a more practical lens.
"There is a self-serving component to love and companionship," he said. "From a biological perspective it's a mechanism whereby natural selection has gotten critters to care for each other. Whatever works, works."