Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
All I know about this short video is the information in the title. It’s ineffably sad and makes me tear up.
Yes, pigs are intelligent, and can you doubt that this is mourning? How does the pig know that its longtime companion is not just sleeping? That’s above my pay grade, but the video bespeaks deep sadness. I weep for the pig who remains.
The Andean Condor (Vultur gryphus) is a bird with one of the longest wingspans in the world—about 3.3 meters, or 10 feet 10 inches. Their mean weight is 11.3 kg (25 lb), with males weighing about a kg more than females. Wikipedia notes that its wingspan is “exceeded only by the wingspans of four seabirds and water birds—the roughly 3.5 m (11 ft 6 in) maximum of the wandering albatross, southern royal albatross, great white pelican and Dalmatian pelican”.
The condor is a denizen of the Andes and a carrion eater, now favoring large dead animals like cows and cattle, though before humans arrived it certainly feasted on the carcasses of native herbivores like guanacos.
A new paper in PNAS (see below) gives data obtained by affixing electronic devices to eight condors, devices that recorded their altitude, whether they flapped their wings (measured by an accelerometer), and how far they traveled using an included GPS. The results are quite amazing: they hardly every flap their wings except when taking off. But I am getting ahead of myself. First, have a look at the soaring behavior of this bird in a 2½-minute video. You can see one desultory wing flap 36 seconds in, and another at 2:20. That’s it.
You can read the PNAS paper for free by clicking on the screenshot below; the pdf is here, and full reference at bottom.
And, at The Conversation, one of the authors, Emily Shepard, describes the study in layperson’s terms (click on screenshot).
The authors caught juvenile condors by luring them down with sheep carcasses, and than affixing clever electronic boxes to the birds, boxes that were designed to fall off after a few days when they were roosting. The data collected was so copious—320 pieces per second, that they couldn’t record it in real time, but had to recover the boxes from the roosting sites and download the data that way.
Here’s a bird being tagged (two photos below from The Conversation piece)
And retrieval of the data box:
The results are unsurprising in one sense, as they found (and we already knew) that these birds soar by using thermals—warm rising air—as well as winds blown upwards when they contact mountain peaks (updrafts). But the surprising thing was how rarely the condors flapped when they were on their foraging flights.
In 235 hours of flight time recorded (1.3 billion data points!), the authors found that condors spend about three hours of the day soaring between roosting and feeding sites, looking for livestock carcasses. The intriguing result was how little wing flapping there was: only about 1% of that time aloft was spent flapping. One striking bit of data came from a single bird who didn’t flap its wings at all for 317 minutes (5 hours, 17 minutes), and yet covered 172 km (107 miles).
This is the lowest amount of flapping of any free-ranging bird, and of course this reduces the energy needed to keep such a large bird aloft. In toto, researchers calculated that 21% of the daily costs of flight were spent in flapping while aloft, while 75% of the costs were involved in takeoff, each such takeoff using the energy equivalent of 3.3 minutes of flapping. Takeoff is onerous, time-consuming, and dangerous, as, say the authors, condors are susceptible to predation then (presumably by large cats like pumas).
Here’s a 25-minute readout from a single soaring condor giving three bits of information: the altitude (top), the heading (middle), and whether they were flapping (“acc” or acceleration), bottom. There appear to have been seven or eight flaps.
The extremely low rate of flapping, using only about 1% of its time aloft, and the bird’s use of thermals and updrafts, explains how such a heavy bird can maintain its lifestyle without expending excessive energy. And the high costs of takeoff explain (along with predation) why these birds roost and nest on high mountain ledges, where they don’t really have to take off, but can simply fall off the ledge and begin soaring.
What are the implications of this work? The authors mention an extinct terrestrial bird, Argentavis magnificens, which apparently weighed about 72 kg—more than six times heavier than the Andean condor. (It’s know from a single humerus, or upper arm bone, which is about as long as a human’s.) Here’s a photo of its size relative to humans and Andean condors:
Wikipedia gives details, and adds that there’s now a fossil species with an even longer wingspan one that would extend to the right side of the figure above!:
Argentavis wingspan estimates varied widely depending on the method used for scaling, i.e. regression analyses or comparisons with the California condor. At one time, wingspans have been published for the species up to 7.5 to 8 m (24 ft 7 in to 26 ft 3 in) but more recent estimates put the wingspan more likely in the range of 5.09 to 6.5 m (16 ft 8 in to 21 ft 4 in). Whether this span could have reached 7 m (23 ft 0 in) appears uncertain per modern authorities. At the time of description, Argentavis was the largest winged bird known to exist but is now known to have been exceeded by another extinct species, Pelagornis sandersi, was described in 2014 as having a typical wingspan of 7 to 7.4 m (23 ft 0 in to 24 ft 3 in). Argentavis had an estimated height when standing on the ground that was roughly equivalent to that of a person, at 1.5 to 1.8 m (4 ft 11 in to 5 ft 11 in), furthermore its total length (from bill tip to tail tip) was approximately 3.5 m (11 ft 6 in).
Argentavis was certainly airborne, and the present work on condors shows that it probably remained aloft by soaring. That, in turn, would imply that it was a scavenger and not a predator, as the latter lifestyle would imply a much more active flight that would be impossible in such a bird. I’ve seen an Andean condor once, in Argentina, and even though it was way up in the sky, it was still impressive. Imagine what it would look like to see an Argentavis magnificens soar past!
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Reader Jacques Hausser, a Swiss biologist, sent some lovely YouTube videos of swifts, who rarely land anywhere, and can’t even take off from the ground. Their diet consists entirely of insects.
The swifts shown are common swifts, Apus apus, which are anything but “common”!
Their most amazing feature (from Wikipedia):
Except when nesting, swifts spend their lives in the air, living on the insects caught in flight; they drink, feed, and often mate and sleep on the wing. Some individuals go 10 months without landing. No other bird spends as much of its life in flight. Their maximum horizontal flying speed is 111.6 km/h. Over a lifetime they can cover millions of kilometers
Their range is shown below (breeding range in red, wintering range in blue):
Jacques’s comments are indented. I highly recommend watching all three videos, which are mesmerizing and will also cheer you up. (Matthew Cobb is a big fan of swifts.)
The first is a general purpose one to celebrate the swifts (7th of June was the swifts’ day, you missed this one—and I missed it too).
The following ones are parts of a study of behaviour in flight (remember, these birds are permanent flyers except in the nesting season).
Grooming in flight:
Capturing prey:
Keas, Nestor notabilis, are the world’s only alpine parrots, found in New Zealand. What is it like to be a kea?
When Tom Nagel wrote his famous article about what it is like to be a bat, he concluded that although bats may have consciousness, the content of that consciousness is inaccessible to us. He’s pretty much right about that, though, as I note below, perhaps some subjective sensations can be sussed out in nonhuman animals. But it would be hard, and probably impossible.
But the way to do this is not the way that the Templeton World Charity Foundation (TWCF) and the John Templeton Foundation (JTF) are doing. They’ve just spent a million dollars on grants to see if animals feel joy. The description of the project is below at stuff.co.nz (click on screenshot).
This is one of those wonky Templeton projects where the organization throws a pot of money at a bizarre issue, one unlikely to have any useful results. I’ll leave it to you to guess whether the results will be anything more than “keas like to do X and don’t like to do Y.”
But I digress. Here’s the project:
Two New Zealand professors have joined a team of international researchers to try to answer one burning question – can animals, like humans, feel emotion?
Experts from Scotland, the United States and New Zealand, including University of Canterbury (UC) associate professor Ximena Nelson and the University of Auckland’s Dr Alex Taylor, are taking part in the joyful by nature research project, funded by the Templeton World Charity Foundation.
The Scottish and American researchers would focus on dolphins and apes, while Nelson and Taylor would focus on New Zealand’s native kea, the world’s only alpine parrot and a species well-known for their unique social attributes.
Experts believe the study could have significant implications for animal welfare and ethics.
. . . . The John Templeton foundation has provided $1 million funding for the research which has been given a three-year term, with an option for a two-year extension.)
(This is a bit confusing, because it seems that two branches of the Templeton Empire are funding the same work.)
First of all, even if we could figure out if keas (or other species) felt “joy” in the same sense we do, would that really have “significant implications for animal welfare and ethics”? I don’t see how. What’s more important is whether they suffer and feel pain, prefer some conditions more than others, and whether we have the right to make animals suffer and die to improve our own well being. Whether they have emotions similar to those of humans is an anthropomorphic and misguided way to formulate an ethical policy.
But, more important is the presently unanswerable question of “do animals like keas experience joy”? Here are the data the article adduces to suggest it:
Many New Zealanders were familiar with kea as cheeky and destructive, but few would realise how remarkably intelligent they were, Nelson said.
“Their cognitive ability is similar or better than many primate species, or humans up to the age of 4,” Nelson said.
Cognitive ability, can, of course, be measured in various ways, and is much easier to assess than emotions. And it could be relevant to animal welfare and ethics. But that’s not what Templeton is funding (my emphasis below).
There were a number of factors into kea behaviour that suggested they feel emotion or joy, Nelson said.
Their babies are raised by adults in crèches, they play and roll around like children, kick stones and dance about and are naturally social creatures, she said.
“They get excited – [their warble] is like laughter.”
Animals develop play behaviour between one another for many reasons. An example of this is young cats or kittens, who play fight to hone their predatory skills. The reason why kea play is unclear.
. . .The lack of any obvious predator allowed kea “spare time” to do whatever they liked, which may have initiated their play behaviours, Nelson said.
Kea also appear to be affected by the seasons, just as humans are and responded in the same way and played in the snow and sun but hid from the rain, she said.
And there you have it: there is an alternative explanation to “play behavior” enacted because it’s fun. It’s enacted because it helps hone skills useful later in life. And, in fact, most ethologists think that play behavior is practice for adult skills (not just predatory ones; my ducks zoom and flap to practice flight motions). It could also be fun, but that would not be its raison d’être. (However, fun or joy could be the proximate stimulus that prompts the animals to begin doing adaptive behaviors.) But in the end the question remains: How do we know whether keas can experience joy?
We can’t, not in any way these researchers could find out. The only way I see to begin addressing this question is to do extensive brain analysis in humans and keas, finding out what areas of the brain (better yet, which neurons are activated) when a human feels joy and when a kea “plays.” If there are consistent neuronal patterns and brain areas associated with joy in humans, and those same areas light up when keas are playing, we might begin to wonder if keas feel something akin to joy.
But we don’t even know the brain patterns of joy in humans, and comparative studies of brain function between humans and birds is fraught with problems. Further, keas are heavily endangered, and looking at their neurons and brains is out of the question.
I thought of one jocular way: teach the keas to speak English and then ask them if they feel joy. You can already figure out the problems with that, though this kind of self-report is how I know that other humans feel joy.
No, at present the question of whether keas (or any other creature, really) can feel joy like we do is unanswerable, and may be forever unanswerable. Templeton has wasted a million bucks, as they do so often, on a dumb project that can’t even address the questions of animal welfare it asks.
Keas, of course, will be protected whether or not they feel joy. We refrain from bashing them on the head not because we know they feel joy, but because they’re amazing animals and are endangered. And if by some miracle we find out they can feel joy, well, that’s not useful for questions of animal welfare: we’d need to look at chickens and ducks and other fowl that we kill or cage.
Templeton, this looks like another million bucks down the drain.
Here’s a kea, photographed by me in New Zealand two years ago:
To make this educational video, some stalwart soul offered themselves as food for a horsefly of the genus Hybomitra. Like mosquitoes, only female horseflies drink blood, and they do so so with fearsome mandibles that contain six sharp blades, or stylets. Here’s a picture by Anthony Thomas of the mandible of a Hybomitra affinis horsefly, showing the stylets(“st”), and below that, one of the stylet blades.
Thomas’s paper also describes the way they bite:
Blood-feeding is accomplished by retracting the labella, the two lobes at the base of the labium [“la” in first picture above), to expose the fascicle of stylets. The long flattened sharp blades of the Mandibles (Fig. 5) are the first of the stylets that enter and cut through a vertebrate’s skin. With its body firmly anchored to the hosts skin/fur/feathers/scales the female fly thrusts its head downwards forcing the mandibles into flesh. Muscles attached to the base of the mandibles move the blades in a side-to-side scissor-like action thus enlarging the initial wound.
And some Fun Horsefly Facts from Wikipedia:
Tabanids are agile fliers; Hybomitra species have been observed to perform aerial manoeuvres similar to those performed by fighter jets, such as the Immelmann turn. Horseflies can lay claim to being the fastest flying insects; the male Hybomitra hinei wrighti has been recorded reaching speeds of up to 145 km (90 mi) per hour when pursuing a female.
In the video below, the bite itself takes place 54 seconds in, and then the hungry lady fills up with blood that will be turned into eggs. I bet you’ll wince a little watching this!
And the YouTube notes:
Hybomitra horse-flies biting and sucking blood. Camera: Canon Powershot SX200 with a +12 diopter close-up lens (a doublet lens from an Elmo Super 8 camera).
Of all the posts I’ve written about the amazing things animals do, testifying to the power of natural selection, this is one of the most amazing. It concerns a very tiny animal, Bathochordaeus stygius, a “giant larvacean”, which is a free-swimming marine tunicate, a chordate in the same phylum as we humans. It’s about 1.5 inches (4 cm) long, with a “trunk” where the organs reside, and a tail that helps it swim and, in this case, pumps water to help it eat. The tail contains the notochord (a stiff rod that we have as embryos; it develops into our spinal column), as well as muscles that are crucial in the activity described here.
Here’s a photo of the naked tuncate from Ocean:
The larvacean is rarely found “naked,” however, for it builds not one but two houses for itself out of mucopolysaccharides (mucus), a big net-like house about a meter across as well as a smaller, complex house (about 10 cm or 4 inches across) in which the animal resides. And both houses are built and discarded every day!
A new paper in Nature, below, tells how researchers used a new laser apparatus in free-swimming animals off Australia to dissect the structure of the inner house to reveal its workings. That inner house, known for a long time, serves not only to protect the animal (it even has an escape hatch that it uses when discarding the inner house or when something bumps it), but mainly to concentrate small organic food particles, which, after being moved through several chambers by the tail undulations, wind up caught in a net by the trunk, where the animal eats it.
The group largely worked from the Monterey Bay Aquarium in California, which produced this wonderful 4-minute video summarizing the paper’s results:
You can also read a short summary at the New York Times, but it’s not all that great, leaving out really interesting information (don’t worry; I’ll supply it):
You can get the article free by clicking on the screenshot below (you must have the legal Unpaywall app), or find the pdf here. The full reference is at the bottom. And don’t miss the five videos, here, especially the one in which they use dye to track the water flow through the house.
The outer net (“oh”) in the (a) bit below, presumably serves (as does the inner house) to deter predators like fish and jellyfish, but also to catch larger food particles that the larvacean couldn’t eat and would clog the filter. It surrounds the inner house, which is quite complicated and serves mainly as a place to filter organic debris and convey it to the mouth of the larvacean. “si” in the first picture is an abandoned house; after being used for just a day, these sink to the sea floor where they and their food-particle contents are consumed by other animals. There are two channels between the outer “net” house and the inner house, allowing food to be transported neatly to near the larvacean:
The structures of the houses, particularly the inner houses, were determined using a “laser-sheet” apparatus called “DeepPIV”, shown below. This was put in the mid-level depths where the larvae reside and laser scans revealed sections of the houses, which were then assembled by computer to regenerate the three-dimensional structures.
Here’s a photo from the New York Times showing the DeepPIV in action:
And the result of the scanning. The larvacean itself is seen in (a) and (b), with (b) also showing the filters by the head (trunk) where the animal can snack on what’s caught. Water comes in the two inlet channels (e), and then is moved by the flapping of the tail through two other channels that move the food to the filters.
Here’s the flow of water through the house as determined by both the laser scanning and dye-injection experiments that track water flow. It’s hard to see how the water moves (but watch the movies); thewater, after traversing the chambers, winds up flowing through two filters beside the head, where the larvacean takes the food. The filters get clogged up after a day or so, and the larvacean discards both the inner and outer houses and builds the two structures anew. That’s got to take a lot of metabolic energy!
And here is the BIG MYSTERY about this whole thing: how do they build the outer net and, especially, that complex inner house? After all, what we have here is essentially a tadpole without limbs, and yet somehow it’s able to construct two complex structures out of mucus, one inside the other. And I’ve bolded what really knocks me over from the paper’s summary:
The greatest remaining mysteries of larvacean houses concern how they are produced. Whereas a spider builds a complicated web one silky strand at a time, the house of a larvacean is extruded all at once as a rudiment and is then inflated. This leads to the question of how a bank of mucus-producing cells can create such an intricate form within a small, tightly packed bubble. Given their remarkable architecture, it seems almost implausible that these complex marvels should be built to last only a day or two. Future observational tools and vehicles will enable us to observe the construction of giant larvacean houses in their entirety, and to precisely document the frequency with which they are built.
It’s constructed compactly and then inflated! How on earth can this tiny creature do that? Well, we have no idea, so there’s lots of work to be done. What is clear is that the houses, inner and outer, are examples of Dawkinsian “extended phenotypes,” structures that aren’t part of the animal’s body itself but can be conceived of as extensions of the animal (like a termite mound or a beaver dam) The behaviors for making the houses must clearly reside in the larvacean’s genome, as the animal doesn’t learn to do this. What a tangled house we build!
This is from Encyclopedia.com:
Larvaceans move their tail inside their house to make a current that filters food particles and moves the house through the water. If the filters become clogged or something bumps the house, the larvacean leaves the house through a trap door. The beginnings of a new house lie on the trunk of the animal’s body, and the larvacean inflates the new house and flips inside.
If you don’t find that stunning, you need to buff up your capacity for wonder!
Finally, just to show that this is by no means the largest invertebrate “extended phenotype” in the sea, here’s a video of a giant siphonophore (a class within the phylum Cnidaria, which includes jellyfish, corals, and sea anemones ) estimated to be 150 feet (46 meters) long. How the individual animals (“zooids”) work as a team, and the advantage of such a length, is yet to be determined.
This commentary is from SciTechDaily:
The discovery of the massive gelatinous string siphonophore — a floating colony of tiny individual zooids that clone themselves thousands of times into specialized bodies that string together to work as a team — was just one of the unique finds among some of the deepest fish and marine invertebrates ever recorded for Western Australia. Scientists from the Western Australian Museum, led by Chief Scientist Dr. Nerida Wilson, were joined by researchers from Curtin University, Geoscience Australia and Scripps Institution of Oceanography in exploring the Ningaloo Canyons in the Indian Ocean. Using an underwater robot, ROV SuBastian, they completed 20 dives at depths of up to 4,500 meters over 181 hours of exploration.
This all reminds me of biologist J. B. S. Haldane’s comment about the cosmos: “My own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose.” The “can” says everything about the limitations of our imagination. Nobody could ever have predicted or guessed that a larvacean like this could exist. Nor a frog, nor almost any other organism!
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Katija, K., Troni, G., Daniels, J. et al. 2020. Revealing enigmatic mucus structures in the deep sea using DeepPIV. Nature (2020). https://doi.org/10.1038/s41586-020-2345-2
The translated Spanish from this video goes like this: “My goldfinch Tweety taking a refreshing dip in my hands, I hope you enjoy it as much as I do.”
I enjoyed it, but it doesn’t look like a goldfinch to me. Readers?