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.

Accidental swallowing can also occur in the animal kingdom.  During 1979-1981, William Dolphin* and Daniel McSweeny were observing eating behavior of humpback whales in Fredrick Sound, Alaska.  At around 3:30 in the afternoon, one of the humpbacks defecated on the surface.  William and Daniel being great scientists took scat samples.  Among the scat and to no surprise was found numerous exoskeletons of krill, one of the primary food sources of humpbacks besides small fish.  However, two unique items for a humpback diet were also found among the scat.

Also included were the remains of two birds, identified by general size and bill shape as Cassin’s Auklets. Feathers were largely lacking and the eyes were missing but otherwise the epidermis was intact and exhibited only superficial signs of digestion.

The auklets’ stomachs also contained krill.  So how did nature construct this version of turducken (krill inside an auklet inside a humpback, krillhumplet)?  Likely the auklets were accidently ingested by the humpbacks as both the birds and whales were feeding on the krill swarm.  William and Daniel estimates indicate more than 150 whales and 2,500 birds were feeding on the same krill swarm at the time.  As Dolphin and McSweeny end their scientific paper “For the auklets this was simply a case of being in the wrong place at the wrong time.”

Of course this pales in comparison to the checklist of items found in the stomach of tiger sharks.

rubber tire, roll of tar paper, roll of chicken wire, bag of potatoes, sack of coal, rags, paper, aluminum foil, beer bottles, burlap sacs, chicken coop [what?], plastic bags, aluminum soft-drink cans, nails, nuts and bolts, 2-pound (1 kilogram) coil of copper wire, small barrels, old pants, overcoats, raincoat, pair of shoes, boots, empty wallet, bag of money (was this off Jersey?), finger ring, driver’s licence, driftwood, pieces of coal, mass of tangled hair, explosives, brass casing from an 18-pound (8 kilogram) shell, tools, leather, fabrics, boat cushions, unopened tin of salmon, 2-pound (1 kilogram) can of peas, cigarette tin, tom-tom, oral contraceptive dispenser, oceanographic drift marker, steak bone, seeds, nuts, grass, jellyfish, conch shells and opercula, horseshoe crabs, tunicates, head and forequarters of a crocodile [shark vs. crocodile!], chickens, pelicans, seagulls, rats, black cat, spaniel with collar, pigs, pig parts, hind legs of sheep, cattle bones and hooves [including a full head], deer antlers, horse parts [including a full head], donkey parts, hyenas, monkeys, and [rarely] human remains.

The tiger shark is so badass it often consumes landbirds like the Yellow-billed Cuckoo, Bahama Yellowthroat, Morning Dove, and Woodthrushes. These likely represent opportunistic feedings on on unsuccessful bird migration attempts over water.

So what does this tell us?  First, tiger sharks are badass and deserving of spot on the 10 species every man should love list.  Second, humans have done a phenomenal job of polluting the ocean.  Seriously a chicken coop, a tire, and explosive?  Third and most importantly, is the peculiar feeding habits of the  tiger shark perhaps represents a beautiful example of evolutionary adaptation.

Despite the fact that the tropical seas it typically inhabits are rather nutrient-poor, this species grows to impressive size – a length of at least 18 feet (5.5 metres) and a mass of more than 2,000 pounds (900 kilograms). Perhaps as an adaptation to its nutrient-poor habitat, the Tiger Shark seems willing to extend its diet to just about anything it can swallow. As though to protect it from its own gastronomic adventurousness, the Tiger Shark has a capacious stomach with a muscular wall that is proportionately some three times thicker than that of any other [shark].

*real name

The post What’s In Your Stomach? first appeared on Deep Sea News.

Some of the language might be NSFW.

The post TGIF – Things You Find in a Shark’s Mouth Edition first appeared on Deep Sea News.

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