A recent study led by researcher Alexandra Childs sheds light on the peculiar behavior of fully grown Galápagos Islands sea lions, who continue to nurse from their mothers well into adulthood. Childs, a PhD candidate in behavioral and marine biology at Germany’s University of Bielefeld, expressed astonishment at this phenomenon, noting that approximately 11% of the sea lion population in the Galápagos exhibit this behavior, which is akin to humans breastfeeding into their teenage and early adult years.
The study, published in the journal the American Naturalist, analyzed two decades’ worth of data on Galápagos sea lions, scientifically known as Zalophus wollebaeki. While most sea lions wean from their mothers between 1.5 and 4.5 years old, the supersucklers defy this norm by continuing to nurse well beyond this age range. The researchers observed instances of multigenerational suckling trains, where multiple generations of sea lions engaged in nursing behaviors.
Andrew Trites, director of the Marine Mammal Research Unit at the University of British Columbia, noted that while similar behavior has been observed in other sea lion and seal species, the extent of supersuckling in the Galápagos sea lions is unprecedented. This behavior is usually associated with food scarcity, with mothers providing extra nutrition to ensure the survival and reproductive success of their offspring.
The study also found that supersuckling was more prevalent during periods of abundant food resources, contradicting the assumption that it occurs due to nutrient scarcity. Childs suggested that this behavior could serve as a bonding mechanism or have immunological benefits, but further research is needed to confirm these hypotheses.
Despite the intriguing findings, researchers caution against drawing definitive conclusions solely based on weather patterns. More extensive studies will be necessary to unravel the mysteries behind the Galápagos sea lions’ unique nursing behavior.