You might have found yourself at some point building a sand castle at the beach or watched your dog dig a massive hole in the backyard. Animals can dig for a variety of reasons: to bury objects, look for food, find shelter or even for fun. Digging can have many advantages including protection from weather, disasters, or predators. In fact, many animals will repeat this behavior or even synchronize (at the same time) digging with other family members.
For the green turtle species Chelonia mydas, synchronous digging from underground nests happens after eggs hatch in order to avoid predators and save energy. A group of researchers led by Hideaki Nishizawa were curious about this unique behavior; they wanted to see if synchronized digging occurred as a result of synchronized egg hatching. This study also measured differences in sand temperature influenced hatching success or digging outcome.
In order to best answer these questions, the researchers placed a microphone in the surface of the sand right above the unhatched turtle eggs. The microphone recorded sounds from the moment the turtles began to hatch until they dug themselves out of the underground nest. The microphone also recorded the temperature of the sand every 10 minutes.
So what did the microphone recordings show? Synchronous digging started before all the eggs in a nest had hatched. This might be explained by the changes in temperature of the sand, as most of the eggs that were heated up hatched faster. This experiment also found interesting results as synchronous digging happened more frequently at night. This raises new questions about the connection between the time of day and sand temperature in digging activity. So next time you are observing an animal in the wild digging, think about the story unfolding before your eyes. Who knew the simple act of digging could be so important?
Works Cited:
Nishizawa, H., Hashimoto, Y., Rusli, M. U., Ichikawa, K., & Joseph, J. (2021, May 19). Sensing underground activity: Diel digging activity pattern during nest escape by sea turtle hatchlings. Animal Behaviour. Retrieved November 10, 2021, from
https://www.sciencedirect.com/science/article/pii/S0003347221001202.
