Monday, August 25, 2014

The Dolphins of Shark Bay

"I am summer, come to lure you away from your computer,
come dance on my fresh grass
dig your toes into my beaches." 
- Oriana Green

Sorry for the lack of blog posts in the past month.  It's a combination of things around here.  Summer in Montana is very, very short.  Already this last weekend the temperature was below 50 degrees!  You need to take advantage of every sunny moment.  At the end of the spring, I read this blog post.  It resonated with my worn out feeling at the end of the spring, when we were finishing up with lots of activities, celebrations, and events.  I decided to take the summer off.  We wouldn't schedule anything, but just be free for whatever came up.  I also made the decision to turn off the cable, so they couldn't just sit down and veg in front of the TV after work and daycare.

So, we've basically spent the summer outside, as much as possible.  We have a plot in our community garden, and a playground behind our house to keep us busy. The girls have also taken out all of their toys and played with them over and over again. This leads to other problems this summer, particularly that our house is always extremely...lived-in.  And between spending lots of quality time together, and cleaning up after said quality time together, there hasn't been very much time to create new blog posts.  I had a vision at the start of the summer that I would use all my "free" time to write posts and catch up on my blog pile.  Instead, thanks to some generous publishers I have been reviewing for, my pile teeters even higher.  But I'm not complaining, honest!  I'm just redoubling my effort to get some posts written.

This book is one of those long overdue posts.  But that doesn't mean I am any less excited to talk about it, just that I haven't had time to write up my thoughts.  I couldn't believe my luck last summer when Pamela S. Turner sent me an email, asking if I'd like a copy of the latest in the Scientist in the Field series, The Dolphins of Shark Bay.  If you've been reading my blog for awhile, you'll know I've reviewed many other books in the series, including here and here.  I was so excited to get this title, another quality, fascinating addition to the Scientist in the Field series,  Plus she sent me the best dolphin notecard, too!

This book takes place in Shark Bay, in the western part of Australia.  Janet Mann is a scientist who has made it her life's passion to study one particular trait pf the dolphins that live there - their tool use.  Now don't get any ideas of dolphins using saws underwater to build new homes.  Even more interesting (and more refined!), they are placing sea sponges on their noses (or rostrums) to help them scrape along the ocean's bottom.  The sponge protects their rostrums as they search for fish hiding in the channel's sand, rock and coral.  Once they unearth a fish, they quickly drop the sponge and gulp the fish.

Dolphins as a species are known for their echolocation skills.  This helps them in many ways - bouncing their sonar off an object helps the dolphin form a three-dimensional image of something in the deeps of the ocean.  They use this information to eat, navigate, find mates and survive.  But the dolphins who are "spongers" aren't using echolocation to find food at all.  Turner describes the dolphins who frequent this part of Shark Bay as searching "half blind" (p. 25) for food.  The channel bottom is covered with rocks and other debris that make it difficult for the dolphins to catch fish.  Conversely, the fish have a better survival rate in the channel's rocks because they aren't discovered as frequently.

So Mann, having seen this behavior performed beginning twenty-five years ago, decided to study this interesting phenomenon more closely.One of the more unusual things she and her research team have found is that this sponging is passed down through dolphin mothers in the pods that frequent Shark Bay.  If you are a dolphin, and your mother didn't sponge, you won't learn that tool use anywhere else.  Mann explains this quirk in this way: "Females are the specialists and the innovators because they're under a lot of pressure to support their calves....If you're a female dolphin who can develop a new way of making a living instead of competing with other dolphins, that's a big advantage.'" (p. 27)

As her team observed more than 600 dolphins, they also documented other unusual feeding techniques - a dolphin who hunts at night, beach hunters (they beach their prey and quickly get back into the water after eating it), and many more specialized behaviors.  These behaviors, too, are often shown in mothers and daughters.  Possibly because mothers have to be smart to get enough fish to feed themselves and their children.  It could also be because daughters stay with their mothers longer than sons do, and see the benefits of these hunting behaviors.

I learned so many interesting facts about dolphins through The Dolphins at Shark Bay.  One chapter looks at alliances of male dolphins and how they bully females into mating with them.  They herd a female away from her group, separating her and badgering her.  Young males practice this strategy on each other to learn teamwork.  They also begin to recognize which other dolphins they might want to form an alliance with.  Along with mating, it really is survival of the fittest in Shark Bay.  All of the adaptations that these pods exhibit help them survive in the wild.

And let me re-emphasize that these dolphins, although observed frequently for research, are wild.  One of the changes that have been made at Shark Bay as a result of Janet's research was to something called dolphin tourism.  When Mann first arrived in the bay, hundreds of people might be in the shallows, throwing fish to the dolphins.  The mothers especially began to learn that the beach was the easiest way to get their babies the food they needed.  SO they stayed near the beach, begging for fish.  As a result, dolphin mothers were overfed, and the only feeding technique babies learned was to head for the beach.  As a result of their knowledge, the government regulates this practice much more strictly.  Only a few volunteers feed selected dolphins a few fish - now the mothers aren't overfed, and the young learn the right way to forage, including sponging.

Finally, Turner does a terrific job of detailing the scientists at work.  She shows one of the team "pole sponging" - imitating the dolphins around him to learn how this works, and why dolphins might engage in it.  She writes about different sampling methods used to monitor the dolphins, and even talks about how they select dolphins to be in the study.  I also really appreciated how when a hypothesis was proven wrong by Mann's team, they worked to come up with alternative hypotheses to solve research questions.  It's all fascinating, and Turner conveys her own enthusiasm for this project throughout the book - she even participates in the research!

Another thing I love about this well-designed series is its inclusion of back matter.  There is an index, additional facts about dolphins, websites, recommended reading, and more citations.  I have always loved how this series develops children's understanding of not only science and research, but the world we live in.  There is tons of material for the interested student to continue learning.  

For one brief moment in my young life, I wanted to be a dolphin trainer.  I had grown up in San Diego and loved dolphins for their intelligence and creativity.  I wish this book had been around when I was young.  I might now be out in Australia with Janet Mann, learning more about these amazing creatures.

The Dolphins of Shark Bay.  By Pamela S. Turner, with photographs by Scott Tuason.  Houghton Mifflin Books for Children, 2013.

sent by the author

No comments:

Post a Comment