When a monkey has twins, she loves one, neglecting the other. She thus fondles the one she loves and keeps him close, while the other child has to take care of himself.
There was once a monkey mother who had given birth to twins. A sound in the jungle scared her. She ran from the danger, holding her beloved twin in her arms, but as she ran, she fell against a rock, and the twin she held in her arms was crushed.
The twin that she neglected, however, who was clinging to her back as she ran, survived without injury.
Inspired by: Mille Fabulae et Una, a collection of Latin fables that I've edited, free to read online. I am not translating the Latin here; instead, I am just telling a 100-word version of the fable.
Notes: This is fable 108 in the book, which is Perry 218. Pliny’s Natural History also mentions that monkeys sometimes kill their children by hugging them too tightly, and the legend of the monkey’s twin offspring, one fortunate and one unfortunate, became part of the bestiary tradition.