Newsflash:

Bats can swim

And are surprisingly good at it

Bats are capable of swimming in stressful situations if the need arises

Some species, such as those belonging to the genus Pteropus (flying foxes), have been known to brave the water to secure a meal#BatStroke pic.twitter.com/ulALyPM1yI

— Laurel Coons (@LaurelCoons) November 11, 2018

And there is of course the Great Fishing Bat. Amazing video here of its impressive catching capabilities. Many apologies for the over-the-top narration.

The post Holy Swimming Bats first appeared on Deep Sea News.

It’s summertime and you’re sweating from the heat and humidity. You jump in the pool and feel a rush of relief as you suddenly feel cooler. The water might not be colder than the air, but it sure feels like it, and it does a great job of relieving you from the heat. We’re all familiar with this, but did you know it may also explain why whales are so big?

Almost 4 years ago, I began my PhD studies at Stanford University. I was interested in how changes in the environment impact biodiversity through time. I first decided to tackle the question of how transitions from land to water impact body size. Mammals are a well-studied group of animals, and they’ve made this transition multiple independent times. There’s also lots of data on their body size, of species in the modern and the fossil record, so they seemed like a great place to start to answer this question. The original goal was just to test whether aquatic mammals are bigger than we expect by chance, but I was really surprised by what we discovered about the drivers of their evolution.

We did (unsurprisingly) find that aquatic mammals are bigger than expected, but also noticed that, despite each group of aquatic mammals evolving from differently sized terrestrial ancestors, they all evolved to the same size of about 500 kg! Even stranger, we found that aquatic mammals are much more constrained in their body size than their terrestrial counterparts! This goes against almost all the reasons why people believe aquatic mammals are big. Once you’re in the water, the idea goes, you should be able to get as big as you want without being hindered by the limitations of gravity and food shortages. Rather, we found that aquatic mammals must get bigger.

After hitting the books, I was shocked that I was able to develop a simple mathematical model that explained the minimum, maximum, and average sizes that we were seeing in aquatic mammals. The minimum constraint in the model shows that these mammals need to produce more energy in their bodies and lose less of that energy, relatively speaking, to the water, to have any energy left over for reproduction and growth. Otters are the one exception to this trend: we’re thinking that this is because they only spend part of their lives in the water or are more efficient at conserving their body heat with their thick fur, although we haven’t been able to test either of those hypotheses yet.

Through developing the model, I also discovered that there’s a maximum limitation on size too. At a certain point, aquatic mammals just can’t eat enough food, no matter how much there is, to sustain larger sizes. For toothed mammals, it appears that this maximum is about the size of a sperm whale. However, baleen whales have figured out a way to eat more efficiently than their toothed cousins, in which they filter entire schools of krill at once from large gulps of water. This feeding strategy seems to allow them to exceed this maximum limit and achieve superwhale sizes.

Long story short, if you want to be a mammal and live in the water for your entire life, you need to get a lot bigger, but you also need to be careful, because you can’t get too much bigger. It’s a tricky balance that aquatic mammals have amazingly mastered at least three times! I’ll stick to my occasional dips in the pool, thank you very much!

The post So, You Want to Live in the Water? A Tale of Why Aquatic Mammals are So Big first appeared on Deep Sea News.

Well it could be any species. Anglerfish, carnivorous sponge, giraffe, or even a montane unicorn.

BUT I WANT TO WRITE ABOUT THE NARWHAL! NOBODY CAN STOP ME!

MWAHAHAHA

Let’s assume that once a species gets closer and closer to this geographic limit it is getting closer and closer to some aspect of the environment that is intolerable for them. For our Narwhal, too far South the temperature is uncomfortably warm. This happens with each of its boundaries on the north, south, east, and west sides. But the center of that geographic range is prime position. Everything is just right. The perfect balance. A Goldilocks scenario. At this place the Narwhal flourishes and the number of that Narwhals is spectacular. This is the Abundant Center Hypothesis. A species is most abundant at the middle of its range. And in the case of our Narwhal, we should find the most of that horned, blubbery beauty right smacked dab in the center of its geographic range.

Graphically, you can think of the Abundant Center Hypothesis as normally distributed bell curve (see above). Pick one of those geographic or environmental axes like temperature or latitude and at the center is peak density or abundance for that organism.

But how well does this actually work in the wild among all animals and plants?

New work by Tad Dallas, Robin Decker, and Alan Hastings at the University of California, Davis sheds some new light on this almost 40-year old question. They recast the Abundant Center Hypothesis into a new testable relationship, if a species is most abundant at their range center, then a negative correlation should exist between abundance and distance from the center—a distance-abundance relationship (above illustration). Overall, the group of scientists examined this relationship for 1,109 birds, 63 fish, 81 mammals, and 166 trees in the Americans.

Overall, distance-abundance relationships like in the figure above were rarely observed. For birds, only 123 out of 1,109 species displayed a negative distance-abundance relationship as predicted. Moreover, 151 birds displayed the exact opposite pattern, their abundances actually increased away from their center. For fish, mammals, and trees combined only 13 negative relationships were found.

So what of the Abundant-Center Hypothesis? Alas, it may be time for the trash bin.
Recovering the predicted relationship for only 9.5% of the organisms tested isn’t exactly impressive. One glimmer of hope remains. The study by Dallas, Decker, and Hasting was for land dwellers. For my beloved Narwhal and other denizens of the sea, they may still be most bountiful at the centermost.

The post Where Do the Most Narwhals Live? first appeared on Deep Sea News.

If dolphins weren’t such a$$holes, they would gently cradle the octopus like a kitten, stroking its mantle and respecting the cephalopod’s amazing intellect. But who are we kidding! This is a dolphin we’re talking about, and marine mammal researchers have found that dolphins “shake and toss” cephalopods like a dog tearing apart his favorite chew toy:

Why is this dolphin such an a$$hole to the octopus? Probably because cephalopods are yummy but dangerous food – they’re smart and sucker-y, and dolphins run the risk of *suffocation* if the octopus isn’t fully torn apart and incapacitated before meal time. As Sprogis et al. (2017) found, death by octopus tentacle is surprisingly common:

It is apparent that octopus handling is a risky behavior, as within our study area a known adult male stranded and a necropsy confirmed the cause of death was from suffocation from a large 2.1 kg octopus.1 The dolphin had attempted to swallow the octopus, however, the octopus was found almost intact, with the head and the mantle of the octopus in the dolphin’s stomach and the 1.3 m long arms separated from the head and extending out of its mouth.1 Similarly, another T. aduncus [dolphin] died from suspected asphyxiation due to an octopus lodged in its mouth and pharynx approximately 140 km north of our study area (Shoalwater Bay Islands Marine Park).2 In these two cases, the dolphins may not have processed the octopus sufficiently by shaking and tossing it to ensure the arm’s reflex withdrawal responses were inactive. Octopus arms have a defensive response, as their receptors can detect stimuli that cause damage to their tissues (Hague et al. 2013). These receptors allow octopus arms to continue reacting even after the arms have been detached from the head, allowing the arms to coordinate a reflex withdrawal response (Hague et al. 2013). Dolphins must therefore process the octopus sufficiently to reduce the arms reflex withdrawal response and limit their suckers adhering to them, which otherwise would make them difficult to swallow.

So mad props to all the octopuses out there, for fighting the good fight against dolphins (and sometimes winning!)

Here’s the frame-by-frame photo in all its glory (Figure 1 from the below paper):

Reference:

Sprogis KR, Raudino HC, Hocking D, Bejder L (2017) Complex prey handling of octopus by bottlenose dolphins (Tursiops aduncus), Marine Mammal Science, doi: 10.1111/mms.12405

The post Reason 5,879 why dolphins are a$$holes: Octopus “handling” first appeared on Deep Sea News.

But seriously though…

The photos seems to have first surfaced on a Reddit group called /r/funny, where members routinely swap amusing photos, real and photoshopped.  This particular photo, which appears to have been photoshopped, was briefly lent credence by a hoax Wikipedia page (“Cranberry Bog Dolphins,” which was almost immediately taken down)

Yes there is no such thing as cranberry bog dolphins.

The post This Thanksgiving Remember the Cranberry Bog Dolphin first appeared on Deep Sea News.

This week the best part of the 90s has returned in full force with the Niantic’s release of Pokémon Go. You guys, this is like that thing when they re-released Oregon Trail for mobile devices…but better.

For those not in the know, Pokémon Go basically blurs the lines between the real world and the virtual world by allowing “Pokétrainers” to catch em’ all as they go through their everyday lives. Quite effectively getting the nerds out into nature to exercise. Sneaky sneaky.

Reports have poured in regarding the rather interesting places people have found themselves looking for wild Pokémon. From strip clubs to delivery rooms, you never know where a Squirtle may be hiding. Perhaps even next to a dead body. 

With that said, I think we can all agree, there are good places to look for Pokémon and very bad, bad places to look for Pokémon. We here at Deep Sea News believe it is our sacred duty to keep the public well informed of all things ocean-faring and would like to point out some of the places that perhaps you shouldn’t go looking for your next Seel or Horsea. You’re welcome.

1. Mariana Trench 

Nearly 7 miles down (36,070 feet), the Mariana Trench clocks in as the deepest point in the world’s oceans. Not only would you not be able to see anything, but the pressures 1,000x that of sea level would crush you and your hopes of catching all the Seadra lurking around in the ocean’s depths. Of course, if you are besties with James Cameron…you might have a chance.

2. Rocky Intertidal Zone

Unlike most of the sea stars on the West Coast of the United States, Starmie’s are immune to Sea Star Wasting Disease so you might actually by lucky enough to find one. However, you must remember that they occupy one of the most extreme ecosystems in the world, the Rocky Intertidal Zone. Thus, in order to be the very best like no one ever was, you must first combat some potentially massive wave action.

3. Hydrothermal Vents

Ironically, there are probably a crap ton of Pokémon at hydrothermal vents and most likely the rarest and most exotic species of all. These vents are teaming with biological diversity uniquely adapted to this most extreme environment comprised of high temperatures and seemingly toxic water. They are adapted…you aren’t.

4. Cook Inlet (Anchorage, Alaska)

Boasting some of the most dramatic tidal exchanges in the United States, this area off the coast of Anchorage, Alaska is no place for Pokétrainers. Krabby and the rest of the water Pokémon won’t get stuck in the quicksand-like glacial silt, but you might. Combine that with a 12.2 m tidal shift and Team Rocket trying to steal your Pokémon will be the least of your worries.   

5. Dead Zone (Gulf of Mexico)

Hypoxic Areas, or Dead Zones, occur when the level of dissolved oxygen in the water column is so low that the area can no longer support aerobic life (note: of which I assume for the sake of this post Pokémon to be). The United States claims domain over one of the second largest hypoxic zones world wide, the Mississippi River mouth in the Northern Gulf of Mexico. This is due, in major part, to large agricultural nutrient run-off. Do not let the photoshopped Squirtle in this picture fool you. There are no Pokémon here. They are all dead.

6. Polar Region

Let’s be real. It’s cold. There is ice everywhere. You don’t have an ice breaker. Though with climate change the way it’s going, catching that Seel might just be a waiting game.  

7. Mediterranean Sea

“The United Nations Environment Programme has estimated that 650,000,000 tons of sewage, 129,000 tons of mineral oil, 60,000 tons of mercury, 3,800 tons of lead and 36,000 tons of phosphates are dumped into the Mediterranean each year.” Probability has it that the Mediterranean Sea is the world’s most polluted ocean, meaning that there are most likely low levels of Pokémon and high levels of “you don’t want to swim there”.

The post The Worst Ocean Environments to “Catch Em’ All” first appeared on Deep Sea News.

Yes, according to a recent study by Lancaster and colleagues.  Many marine mammals are precocial in that the young are relatively mature and mobile from the moment of birth. Juvenile dolphins for example are independently swim, surface to breathe, and maintain contact with mother on their own.  But how developed is the hearing of a juvenile dolphin?  Are their tiny, little ears fully formed?  Alright so maybe they do not have ears per se just ear openings but you get the drift.

Inside a vertebrate skulls, including the dolphin, is an area referred to as the tympanic or auditory bullae.  These hollow, spherical, bony structures are on the bottom, back portion of the skull and enclose parts of the middle and inner ear.  Lancaster and colleagues found in two species of dolphins, the Common Bottlenose and the La Plata, the tympanic bulla is same size in adults and juveniles, despite the smaller skulls and bodies of the young.  Why would juveniles have adult-sized “ears”?

The size, shape, and material of a structure determine its resonance frequency, i.e. the detectable auditory frequencies.  If dolphins vocalize at a certain frequency then the size of the tympanic bulla needs to match this—even in juveniles.  If young had a smaller ears the parents may just sound like Charlie Brown parents. As the authors state, “The fact that the overall structure of
this [auditory] architecture has remained relatively constant throughout the last 45 million
years of cetacean evolution indicates that it was an early and essential adaptation for
underwater sound reception and hearing.”

The post Do baby dolphins hear their parents? first appeared on Deep Sea News.

For those of us who love the spineless weirdoes of the ocean, it can get old always hearing about the dolphins and the whales, the sharks and the fish and the turtles that everyone loves so much (and that have a disproportionate representation in our culture: just think of all that Lisa Frank swag from the nineties).

Fellow invert nerds, please enjoy these gifs of invertebrates punching vertebrates in the face.

1. Giant isopod vs. shark

2. Sand Striker vs. fish

3. Giant Pacific octopus vs. shark

4. Mantis shrimp vs. fish

5. Sea stars and nemerteans vs. seal

6. Octopus vs. cat

The post 6 times an invertebrate punched a vertebrate in the face (and it was awesome) first appeared on Deep Sea News.

7. Stingray eating a crab

9. Deep-sea crab eating a Giant Isopod

The post Top 10 GIFs of Ocean Animals Eating Other Animals first appeared on Deep Sea News.

K. Now, let’s all take a moment to appreciate the wonderful person who populated Wikipedia’s “List of Cetaceans” article with these:

To anonymous editor on 19 December 2012: thank you. You made my Tuesday.

The post Awesome nerd joke hidden in Wikipedia’s “List of Cetaceans” first appeared on Deep Sea News.