Interested in reading the full article? Access our peer-reviewed manuscript in Evolutionary Ecology

“Some things in life are worth fighting for. . .” — for animals the defense of space, known as territoriality, usually functions to safeguard valuable resources like food and mates. However, for a remote species of tropical frog, we have recently discovered a surprising addition to things that adults find worth defending: suitable nurseries.

Human parents are well aware of the lengths some will go to to secure a first-rate nursery school for their children. Oddly enough, a parallel can be found on top of the world’s tallest single-drop waterfall (Kaieteur Falls, Guyana) where there exists the only known population of golden-coloured rocket frogs (Anomaloglossus beebei). These small poison frogs spend their entire development in giant tank bromeliads (i.e., 2-4 meters tall, Brocchina micrantha): within these plants, eggs are laid in the lower leaves and hatch as tadpoles. Fathers then transport their young to water-filled leaf axils higher in the plant through an elaborate piggyback ritual where tadpoles cling to a father’s back. Tadpoles must survive in selected leaf axils until metamorphosis, meaning the quality of a nursery can have profound implications for the success of the tadpoles contained within them.

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Of course, if a frog’s only suitable breeding-ground is on top of an isolated waterfall in the middle of the Guyanian Amazon, it isn’t surprising that there isn’t room for everyone. Thus, in addition to their intense parental care duties, male rocket-frogs are extremely territorial and aggressively defend established areas in bromeliads (which consist of multiple leaves) from potential intruders. Along with Johana Goyes Vallejos (University of Missouri) and James Tumulty (College of William and Mary) we wondered if the intense territoriality of males had any relationship to their intensive care-giving duties. In a bromeliad, what is the function of the space males are defending? Our study, recently published in Evolutionary Ecology, consisted of first characterizing leaf axils in bromeliads to understand the differences between pools that were used as nurseries versus those that were not. Once having established the “high-quality” parameters that characterized occupied pools, we took advantage of Tumulty’s long-term mark-recapture dataset to see if the location of high-quality nurseries coincided with the territories of established males. Indeed, these characteristic pools occurred significantly more frequently within defended territories.

In other words, males defend areas that may benefit their reproductive output in a non-immediate future– a cognitive feat of future planning that is not typically associated with amphibians.

In human terms, these parents are securing spots in Montessori schools before they were even pregnant.

The combination of the geographical isolation and specialized behaviors that characterize golden rocket frogs make them a key species to unlock our understanding of the evolution of parental care and cognition in amphibians and beyond.