Vaquita: Behavior

Summary: Vaquita behavior is another fascinating thing about this unknown animal! Join Kiersten as she gives you a glimpse into the behavior of vaquita marina.

 

For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.

 

Show Notes:

https://www.aquariumofpacific.org/onlinelearningcenter/species/vaquita

https://porpoise.org/save-the-vaquita/

Vaquita: Science, Politics, and Crime in the Sea of Cortez by Brooke Bessesen

Vaquita Conservation Organizations

Porpoise.org

 

Transcript

(Piano music plays)

Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.

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Kiersten - Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 

 

This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.

 

This episode continues the vaquita and the third thing I like about the vaquita is their behavior!

 

As we have already established in the first episode, vaquita’s are marine mammals, specifically, cetaceans. That means they live their entire lives in the water. The vaquita is a porpoise that lives in warmer waters than other cetaceans, but they are still sea dwelling animals. Being mammals, they do breath air and, just like many other cetaceans, they have a hole on the top of their head that allows them to release carbon dioxide when they surface and breath in fresh oxygen. This hole is called a blowhole and it’s a lot like our nose. They are able to open and close it with muscles, so they can hold their breath under water and keep the water from flooding in when they dive down. Okay! We have to use our fingers to do that with our noses, but still both orifices that we breath through!

 

Because of this physical need they must come to the surface, but they are extremely shy, secretive animals. Unlike their dolphin cousins, you will not see vaquitas leaping out of the water performing gravity defying acrobatics or frolicking in the wake of passing ships. They are very subdued when they visit the surface and rise slowly with a forward-rolling motion that hardly disturbs the water as they take a breath and then quickly disappear back into the depths of the Sea of Cortez. 

 

These small marine mammals are incredibly sensitive to passing ships and will not surface if they sense one. It is extremely difficult to observe them in the wild because they can be disturbed by boats passing within a mile of their location. This makes it incredibly difficult to study them, and this created another unforeseen challenge for conservationists. Many people do not believe vaquita even exist. 

 

For residents of the region surrounding the Sea of Cortez, the myth of the vaquita has been around for decades. Many residents do not believe they are real, living, breathing animals. They are like a unicorn or the Loch Ness monster, just something you talk about but never see because they’re not actually real. (Before anyone gets too upset, I’m not saying unicorns or the Loch Ness monster aren’t real, just that we have no tangible evidence to prove their existence….yet.  That’s a whole other podcast! On the other hand, we have a lot of evidence proving the vaquitas existence!) 

 

The main problem for conservationists is how do you encourage people to save an animal if they think it’s a mythological creature. When dead vaquita began to wash up on shore with more frequency, as sad as that is, devastatingly sad, conservationists thought this would prove their existence but some still believe they are a myth and these are photoshopped pictures or man-made dummies. Most fisherman know that they are real as thy have seen them or seen evidence of them, but they often deny it because it’s better for them if the vaquita remains a myth. Take my word for it listeners, vaquita are real! I promise you!

 

Vaquita are often solitary or travel in pairs, which is another reason they are not easily seen, but a few groups up to 8 individuals have been found. It is more likely when a couple is seen together, it’s a mother and a calf. 

 

Now, little is actually known about vaquitas reproduction, but researchers believe it is similar to harbor porpoises, which is their closest relative. Based on this, we are comfortable making a few assumptions about vaquita reproduction.  Vaquitas probably reach sexual maturity between 3 to 6 years. They can live uo to 20 years. The gestation period is 10-11 months and vaquita will give live birth to one calf every other year. The calves will be about 2 1/2 feet long at birth and can weigh 17 pounds. They will most likely nurse for about 6 to 8 months. All of this combined means that vaquita are very slow at reproducing.

 

When they are ready to eat sold food, they’ll become hunters like their mothers. Just like other species of porpoises, vaquitas echolocate to find food. How exactly does this work? Excellent question listeners? 

 

As Brooke Bessesen, I apologize if I’m saying that incorrectly, describes in her book Vaquita: Science, Politics , and Crime in the Sea of Cortez, “Porpoises make high-frequency clicks that bounce off objects and echo back, giving them an auditory “image” of scenes and objects. The fatty crown on the porpoise’s head, called the melon, emits and focuses ticks like a sound lens, while incoming reverberations, received through the thin, lipid-covered bones of the lower jaw, are directed to the inner ear.” Using this method is how porpoises can hunt and find their food. 

 

Through the research of Mexican acoustic expert Armando Jaramillo Legorreta we know that vaquita clicks are typically between 128 and 139 kilohertz. This is well above the ability of human hearing, which is 20 kilohertz max, but with specialized equipment their clicks can be recorded. According to Armando, vaquita make narrow band clicks. 

 

In your mind you may be thinking about the noises dolphins make, the whistles and clicks we can hear. Those of you who have been to a dolphin experience or show or those of you who remember the television show Flipper, ( I have just revealed my age with thane!) know what I mean! They have a much wider range of acoustic ability than vaquita. Our small vaquita marina is not capable of dolphin-like chatter, but it doesn’t make them any less adorable.

 

In some animals, such as dolphins, acoustic clicks are used for more than just hunting prey. They are also used for communication. We do not know whether this is something that vaquitas do as well, but we do know that their clicks increase in frequency when they are hunting. Vaquita will hunt at least 20 different marine species such as bronze-striped grunts, gulf croakers, small crabs, and squid. These are all mostly bottom dwelling species. 

 

It makes total sense that vaquita rely on their echolocation skills to hunt because the Sea of Cortez is very turbulent, making the water murky. Vision is fairly useless in these waters. The terrain under the water is also filled with ridges and valleys that vaquita can learn by using their echolocation.

 

By slowing down the clicks and click trains recorded using fancy acoustic equipment, humans can hear the sonar of certain animals, such bats and blue whales. When Brooke Bessesen was researching her book she asked if any researchers had done that to the vaquita calls. Someone had tried, but they’d only done it one because when you slow down their click trains it sounds too much like a fart to take it seriously. 

 

 I’m glad you all joined me in this glimpse at the vaquita’s behavior, it is my third favorite thing about them.

 

Please visit porpoise.org to find out even more about the vaquita and to discover what you can do to help this unique animals.

 

Join me next week for another ten-minute episode focusing on the vaquita. 

 

(Piano Music plays) 

This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.