what makes a dolphin's house a home?

Professional dolphin care specialists are always observing the animals under their care to monitor how they are interacting with each other, their enrichment, and their habitat. These interactions can serve as an indicator of how appropriate a habitat is for an individual or group. For example, if a group of animals does not often use a portion of their habitat, it may be because there is nothing of interest present. Adding enrichment for animals to find in that part of the habitat increases its complexity and makes it more interesting to the residents. Unlike many terrestrial mammals, dolphins use not only the horizontal space in their habitats but also the vertical space. This means that researchers must take a 3D approach to studying dolphin’s habitat use.

To learn more about how bottlenose dolphins use their habitats, we studied the relationship between the ways dolphins use their habitat and a wide range of demographic, environmental, and management factors with dolphins in 44 zoos and aquariums around the world. First, we looked at how much time dolphins spent in different depths by dividing the habitat into vertical thirds: top, middle, and bottom. Second, we examined how long their dives underwater were.

We found that dolphins with more complex enrichment programs spent more time at the bottom at the habitat and had longer dive durations. Receiving new enrichment at least once a month was also related to spending more time at the bottom of the habitat. This may be because the new enrichment includes sinking items or activities that encourage the dolphins to explore the bottom of the habitat. It is not only enrichment that makes a difference though! Creating smaller social groups during the day and reuniting them at night was related to spending more time in the middle and bottom parts of the habitat. In addition, dolphins that had groups with continuously rotating membership spent less time in the bottom third of the habitat when compared to those who lived with the same group all the time. Wild bottlenose dolphins live in fission-fusion societies where individuals in the group change over time. A dynamic social group with separations and reunions may be an important component of dolphin’s social lives. We also examined how physical differences in habitats, such as the volume, length, and depth were related to habitat. However, we did not find any relationship between the how the habitat was used and its physical characteristics.

What does this all mean? The study results suggested if dolphins are in an appropriately sized habitat that the enrichment program and their social groupings may play a greater role in how dolphins use their habitat compared to the exact volume, shape, or depth. Zoos and aquariums around the world can use these findings to inform their initiatives to ensure that the dolphins are getting the most from their habitats!

Lisa Lauderdale, Ph.D.
Animal Welfare Scientist
Published November 3, 2023