Behavioral changes as a result of experience: The curious case of the cane toad

Background/Question/Methods

An individual’s ability to modify its behavior as a result of experience is a key component of survival in a changing environment. Cane toads (Rhinella marina) are known for successful colonization of new environments, however there is little indication from the literature that anurans can learn. This study examines how cane toad exploratory behavior and foraging success changes as a result of experience in a novel area.

      Wild-caught cane toads from their native range were tested in an exploratory arena with or without food present. We tested whether movement and behavior strategies changed as a function of experience in the arena, and whether these behaviors were modulated by the presence of known food sources. After an initial training period toads were tested in the arena for 60 minutes every other day for a total of 5 trials. A final trial was conducted to determine what types of cues toads were using to located food in the environment. We used Ethovision XT to track toads during trials and measure variables related to movement. 

Results/Conclusions

We found that toads in both treatment groups significantly decreased time spent moving, total path length, time spent in the margin and number of escape attempts as experience in the novel environment increased. Additionally, toads without food present in the arena decreased the number of total and unique bowls encountered during trials, while toads with food present visited a slightly higher number of different bowls over time. We also found that toads in the experimental treatment increased the number of mealworms eaten with each successive trial and directness of path to the food bowl, however latencies to leave the starting point of find a food bowl did not change as experience increased.

The results of this study show that cane toad behavior is modulated by experience with a novel environment. One the whole, cane toads explore less as experience increases, suggesting that they are able to recall information previously gathered about the environment. This study emphasizes the role of learning in foraging in cane toads, a characteristic that may have facilitated their success as invaders.