I had to put up this video because it’s so cool and unusual (Matthew alerted me to it). It’s a cormorant grabbing remoras affixed to the skin of a whale shark off Cabo San Lucas, and a one-off video. (Remember that the whale shark, Rhincodon typus, is the world’s largest fish.)
Now that is avian inventiveness!
Earth Touch News Network says this:
Fishing is time-consuming business, so diving birds in Mexico’s Baja California are frequenting the local “sushi conveyor” instead. That conveyor comes in the hulking shape of the region’s reigning big fish: the whale shark. The crafty cormorants have figured out that the giant sharks provide an endless supply of remora sashimi.
In the clip, a diving cormorant yanks furiously at a remora fish attached to the skin of a passing whale shark, before finally pulling its meal free. It’s a truly remarkable sighting – in fact, this footage filmed back in 2012 may be the first (and only) example of its kind. According to marine biologist Dr Simon Pierce, who has done extensive work on whale sharks, experts have been excitedly discussing the video since it started making the rounds online earlier this week.
“It’s super cool!” he says. “I don’t think it’s been documented. I’ve never seen or heard of it previously, but that particular cormorant certainly knew what it was doing. Smart bird!”
An extended clip released by Manta Scuba Diving [JAC: this clip] confirms the event was no once-off: after its initial catch, the bird – likely a Neotropic cormorant or double-crested cormorant (Phalacrocorax brasilianus or Phalacrocorax auritus) – came back for both second breakfast and elevenses.
But wait! There’s more! (My emphasis.):
Remoras attach to their host species (animals like sharks, cetaceans and sea turtles, as well as the odd ship or human diver) using a slatted sucking disc located above the eyes. Once in place, the hitchhikers cruise along effortlessly, ready to gobble up any morsels that float their way.
The immense size of whale sharks offers particularly spacious real estate for remoras – some individuals cart dozens of the freeloaders around – so it’s not entirely surprising that local birds have learned to capitalise on such an abundant food source.
Roominess aside, there’s another reason remoras cling to whale sharks in such large numbers: poop. While it was long believed that the remora diet comprised mainly of their hosts’ mealtime leftovers, scientists have since discovered that the suckerfish prefer to dine on something a bit more plentiful. And you don’t get much more abundant than a whale-shark poop cloud: the animals can drop 56,000 litres in one go.
“(…)in one go.”
Genius writer
Watching footage of Chondrichthyes towing Osteichthyes who are being eaten by a semi-aquatic Theropod dinosaur.
What more do you need in the morning?
56,000 liters…If that were all water, it’d outweigh the largest confirmed individual (21 Tons, per Wikipedia) by a factor of more than 2. Something’s off.
Thinking further about it, 56,000 liters is ~1977 cubic feet. That’s a 7’ square, 40’ long.
SEE THIS LINK from the same source [with ridiculously insignificant digits left as I found them!]:
They are stating the volume of the plume which would include the seawater mixed with the poop. Both the quantity measured and its precision are silly.
Yes, it can’t be otherwise.
Hmmm. “Can’t be otherwise”?
My strategy for estimating the volume of an excretion would follow Mrs Beaton. “First, catch your” whale shark and prepare it for dissection. (Details left as an exercise for the student.) Measure the distended diameter and length of the terminal section of the gut. Use that as your estimate for the pre-dilution volume of a whale shark defaecation. I don’t know enough about the anatomy of whale sharks to say where the gut changes from “food processing” to “excrement storage”, but many sharks have a “spiral valve” running much of the length of their lower gut, which appears to be a surface-area increasing structure. Unless told differently, I’d suspect the end f that structure too indicate the end of food processing and possibly the change to excrement storage.
Indeed.
Birds are damned smart. The cormorant looks ancient and primitive but they seem to have intellectual talent. Perhaps they rival Corvidae. Let’s see a matchup.
Not bird-brains at all!
These remoras: easy to catch, but not so easy to pry loose. Still I guess that a big fish like the whale shark is a bounty for the cormorants. Stunning footage!
As for intelligence, these dinosaurs have nothing to be ashamed of compared to mammals. IIRC, I think there were a few posts on this site about the intelligence of crows and parrots, cormorants appear to be in that league.
Whoa, now that was cool!
How cool is that?!
Love the way the corms are so in their element in the water–good at holding their breath, too.