Dynamic Dolphins

Palm trees, sandy beaches, and blue water…Oh my! Doesn’t that just sound amazing? Well last summer (2013) I was lucky enough to experience all of those on a cruise to the Bahamas and it was absolutely wonderful. One of our stops on our trip was to Freeport, Bahamas. As most people know, when you stop somewhere while on a cruise, most people get off and go on excursions. My family decided to do this and I am so glad we did because it was probably my favorite part of the trip. You may not know this about me but I have an obsession with animals; mostly ones with fur such as dogs and cats, but I also am a big marine animal lover (one of the reasons I was dying to take marine biology). I love sea turtles and was actually able to swim with them when I went to Hawaii a few years ago, but one of my life goals had always been to swim with a dolphin. Well guess what? I can put a check mark next to swimming with dolphins on my bucket list because that life goal has now been completed! And let me tell you, it was amazing. We got to hang out with two male dolphins, who were brothers, and they were remarkably smart and cute.

                   This is a picture of me on the trip! 

This experience has only increased my interest in dolphins. I already knew dolphins are very intelligent animals known for their agility and playful behavior, but researching online I found out about an interesting study known as the Shark Bay Dolphin Project. It started in 1982 when two American researchers flew half-way around the world to a remote bay in Western Australia, at the Monkey Mia beach. There, they found a small group of wild bottlenose dolphins that would swim right into shore to be hand-fed by humans. From these few animals, their research expanded to include hundreds of Shark Bay dolphins, and their visit led to the establishment of an extensive long-term study of the population. The long-term records of the animals are being managed in a database at Georgetown University.

The main reason these dolphins are be researched is due to the unique window it provides into the dolphin society. From this research, the dolphins are being protected as well as providing information on the effects of provisioning on wild animals. Research performed includes hundreds of dolphins that are surveyed and cataloged each year. Their behavior, ecology, genetics, development, communication, and various other aspects are all being recorded, making this one of the most important dolphin research sites world-wide. What I also love about this is that it is all accomplished non-invasively, without tagging or capturing the dolphins. 

When looking at different articles about dolphins, an interesting aspect I came across is the mystery of why dolphins have evolved such big brains. Bottlenose dolphins have the largest brains outside of humans when body size is taken into account. Why do they need such large brains? The Shark Bay Dolphin Research Project has revealed that dolphins, like some large brained terrestrial mammals, lead highly complex social lives. Complex social relationships are thought to have played an important role in the evolution of large brains in elephants, apes, and humans, so it is believed to be the reason it is seen in dolphins as well.

Another study being performed in Australia can be found at Shark Bay, called the Shark Bay Ecosystem Research Project. Shark Bay is in remote Western Australia and is home to a large sea grass ecosystem. Its remote location and small human population have made it a safe place for organisms such as tiger sharks, sea turtles, and of course dolphins, to thrive.  

The male dolphins of Shark Bay are known to marine biologists for their social entanglements. Their relationships with each other are so unusual that one team of scientists argues that the dolphins live in a social system that is known to be quite unique among mammals. Researchers suggest that these complex relationships may stem in part from one simple factor: the dolphins' low cruising speed, which may lead to social smarts. Because the Shark Bay dolphin population is large and has overlapping territories, it doesn't take long for one group of dolphins moving at their normal speed to meet up with another, possibly competitive, group. In these situations, the dolphins are forced to do the two things that may enhance social cognition: make friends and form group alliances.

In yet another study, it was seen that dolphins have a large cerebellum and the findings from this research suggest this is due to motor and sensory processing. The scientists linked this information and sensory processing to echolocation (Marino). Echolocation is when high frequency sound waves are emitted by the animal and the echoes are picked up and rapidly processed.

So, it seems to be that the brain size of dolphins is still somewhat of a mystery. Is it due to social relationships, cruising speed, or echolocation? Although it may not be fully determined, it is no mystery how amazing these animals are. I hope the dolphins continue to thrive in these Australian waters. I also hope we get the chance to see them on our trip to the Outer Banks!

Here is a video I found of two dolphins playing near a boat, kind of scary how close they are! 

Reference:

Marino, L., Rilling, J.K., Lin, S.K., & Ridgway, S.H. (2000). Relative Volume of the Cerebellum in Dolphins and Comparison with Anthropoid Primates. Brain, Behavior & Evolution. Doi:10.1159/000047205