El Niño atmospheric oscillations over the Pacific Ocean wreak havoc on monkey populations, either in the midst of the periodic hot and dry spells or in their chilly aftermath, according to the results of a new study.
The study, published in the October 28 issue of Biology Letters, explored the correlation of El Niño years, when above normal temperatures in the Tropical Pacific cause drought and flooding in different parts of the world, with fluctuations in monkey populations and the abundance of their food resources. It is the first report on the impact of El Niño on monkey species that live in Central and South America, many of which are threatened or endangered. The study focused on four species: red howler monkeys (Alouatta seniculus), which subside primarily on leaves, along with two species of woolly monkeys (Brachyteles arachnoides and Lagothrix lagotricha), and a variety of spider monkey (Ateles geoffroyi), all of whose staple diet is fruit.
"I thought it was interesting when I got [the] results that the howlers were declining in the same year [as an El Niño], and the other three species were declining the same year" that followed El Niño events, says Ruscena Wiederholt, a graduate student of ecology at The Pennsylvania State University's Huck Institutes of the Life Sciences, and first author on the study.
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