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.
Thank Ceiling Cat: two readers came through with photos when the tank was empty. Today’s lot comes from Leo Glenn, who sends photos from Costa Rica. His captions are indented, and you can enlarge the photos by clicking on them.
Here are some more photos from my recent trip to Costa Rica.
There are four species of monkeys in Costa Rica: the Central American squirrel monkey (Saimiri oerstedii), the Panamanian white-faced capuchin (Cebus imitator), Geoffroy’s spider monkey (Ateles geoffroyi), and the mantled howler monkey (Alouatta palliata). As we were spending most of our time in parks and nature preserves, we were hopeful that we would see at least one of the species. It came as quite a surprise to us, then, that while we saw no monkeys in any of the nature preserves, a family of mantled howlers moved Into the trees next to our rental house and spent around 45 minutes eating, lounging, and playing. It was an amazing experience.
Like cats, they were masters at relaxing in the most precarious of positions.
We enjoyed watching them use their prehensile tails to move among the branches, sometimes hanging from them to reach the choicest leaves, which make up 75% of their diet.
Another species that we were hoping to catch a glimpse of was a coatimundi. And just as we pulled into the Monteverde Cloud Forest Reserve, a South American coatimundi (Nasua nasua) strolled right across the parking lot.
Coatimundis, known locally as pizotes, are members of the family Procyonidae, the same family as raccoons, and they share many of the same traits. Unlike the more nocturnal raccoons, however, coatimundis are diurnal.
In the cloud forest, we came upon a nest of red-tailed stingless bees (Trigona fulviventris). Our guide said that the honey they produce is inedible, but it has been used traditionally for medicinal purposes. I couldn’t find any information on that, but I did read that the sticky resin they make to build their nests has been used by fishermen to caulk leaks in their canoes. Another occasion when I wished I had a longer lens.
A tree fern (Cyathea holdridgeana). I was particularly excited to see this, as I have been obsessed with paleontology since I was a child. Tree ferns, along with Lycopods and Horsetails, were the predominant “trees” in ancient forests, before our current trees evolved. This particular species grows at elevations of 2400-2800 m, much higher than most other tree ferns in Central America. I believe we were at around 2100 m on this tour.
A colorful group of caterpillars. I was unable to determine the species, but they appear to be a moth in the genus Euglyphis.
And finally, our rental house came with a cat [Felis catus], whose name was Linda.
Linda asking to be let in.
Below: Linda’s favorite activity, after we let her in (other than begging for something to eat). She was 17 years old, and growing deaf. Her meow was loud enough to wake the dead (something she liked to do at five in the morning outside our bedroom window). But she was otherwise spry and hale. Of course we fell in love with her.
Reader Mike Canzoneri sent some photos of squirrel monkeys, which you can enlarge by clicking on them. He also sent a brief bio:
I was born and raised in the city of Chicago and have been a backyard zoologist since I was a little kid. I moved to Miami, FL in 1990 to be close to Everglades National Park (where I was a volunteer), then to Austin, TX in 1994 (for a better job) and finally to Costa Rica in 2005, where I spent my meager nest egg on three separate rain forest properties. I built a house on my southern Pacific coast rain forest property (about 100 acres) and live there most of the time.
Mike’s captions are indented, and you can enlarge the photos by clicking on them.
In January and February, the females give birth and the babies stay on their mothers’ backs until well into summer. Once the babies are close to the size of their mothers, the mothers try to shake them off but the babies resist for as long as they can.
All shots taken with my Nikon D850 and either the Nikkor 300mm f/4 or 500mm f/5.6 PF prime lens, except this first one taken with my Nikon D750 and Nikkor 500mm f/5.6 PF.
The mothers wear the babies like backpacks as they run up and down the trees and jump from one tree to the next, and they get tired and need to rest from time to time. I caught this mother doing a face plant into the bamboo to take a 30 second power nap.
I notice that the mothers try to help each other and stick together. I was lucky enough to be ready with my camera when this scene played out in front of me, where two mothers, each with a baby, all engaged in a group hug.
I’m not sure what had this baby’s attention but I liked the way the photo came out.
This baby was pushed off by its mother so she could take a break. She didn’t go too far and the baby clung to the branch, frozen in fear, until the mother came back a few minutes later.
Here is a shot of a mother nursing her baby.
Taken about two minutes after the shot right above, here is the baby holding on tightly to the mother.
Here’s a juvenile squirrel monkey just hanging out in a small tree.
To end the set I chose this photo of a juvenile gazing pensively up at the canopy.
Today we have a variety of photos from Daniel Shoskes. The species are unidentified, but readers can help with that. Click on the photos to enlarge them; Daniel’s notes are indented.
From a cruise down the Peruvian Amazon organized by Natural Habitat Adventures (affiliated with the World Wildlife Fund). Have video with a glimpse of the elusive freshwater river pink dolphin but not photos.
If you’re idle during the holidays, do send in some photos. I ain’t going to Poland, so the feature can continue—if people contribute.
Today we have the third batch of photos from Rosemary Alles (part 1 is here and part 2 is here), featuring the creatures of South Africa. As I posted before:
Today’s photos come from Rosemary Alles, who lives in South Africa and works for a conservation organization that partners with local people. Her narrative and captions are indented, and you can enlarge the photos by clicking on them. This is only part of a larger set: more photos will come later.
I am an American living (temporarily) in SA. These pics were taken from my small studio in rural South Africa and while within the greater Kruger region. I am originally from Sri-Lanka, a war-torn nation just to the south of India. My family and I immigrated to the west to escape a violent civil war in Lanka.
You can find more about us (the work our org does) here. We focus primarily on indigenous women/children at the intersection of conservation.
Click on the photos to enlarge them.
Two photos of a male duiker antelope (JAC: either red or gray; I don’t know):
Here’s a short new paper from Proc. Nat. Acad. Sci. that, in fact, reports just a single gesture of one chimpanzee towards another. Was that worth a whole paper? Well, it appears to document the first example of “referential gesturing” in any animal other than humans.
What is a “referential gesture”? It’s a gesture that one individual could make to call attention of another individual to something, usually involving an object, an action, or a third party. (This is how humans use such gestures.) Pointing is one of these actions (you all know that when you point at something to a dog or cat, they look at your hand, not what you’re pointing at!).
In this case, one chimp held out a leaf to another chimp, and when the second chimp didn’t respond, the leaf-holder moved it towards the other’s face to call more attention to it. Click on the screenshot below to see the paper, which has free access, and you can find the pdf here.
The behavior is connected with the way chimps groom themselves to get rid of parasites and keep themselves clean. Sometimes they also appear to groom leaves—for reasons unknown. I’ll reproduce the report of the one gesture involving a chimp who was grooming a leaf.
We recorded an instance of a referential showing gesture between conspecifics in the context of leaf grooming in the Ngogo chimpanzee community, Kibale National Park, Uganda that seems to be produced declaratively. During self-grooming or social grooming, groomers occasionally pluck leaves that they manipulate with their fingers and mouths as if grooming them while also peering closely at them. They may be inspecting ectoparasites (e.g., ticks) they have placed on the leaves, but the function of leaf grooming remains unexplored in this community. The event described here involved a mother/adult daughter dyad. Adult female Fiona was sitting next to her mother Sutherland, whom she had been grooming. Fiona plucked a leaf from a small sapling and started leaf grooming. Sutherland’s attention was focused elsewhere while Fiona did this (Fig. 1 and Video S1), and after grooming the leaf for several seconds, Fiona held it out toward Sutherland. She repositioned her arm when the initial holdout did not elicit a response (Fig. 1). Once Sutherland attended to the leaf by fully orienting her eyes and head toward it, Fiona retracted it and continued leaf grooming.
It’s already known that chimps (and other species) use gestures to indicate what they want from others, like food or grooming, and here’s a video of such gestures:
But these aren’t referential gestures showing something to another chimp just to get its attention. As we’ll see shortly, Fiona apparently wasn’t offering the leaf to her mother to say, “here’s something for you to eat” or “here’s something we can eat”, but, according to the authors, the gesture was meant to get Sutherland’s attention, meaning roughly, “Have a look at this.” Fortunately, the gesture was filmed by the researchers, and here it is. Note how Fiona moves the leaf around until the object has Sutherland’s full attention.
The authors dissect this gesture to show that it’s truly referential:
The movements of this behavior are in line with the definition of showing or “holdouts” in human infant literature. Using the operational definitions of the most recent research on infant showing and giving, this gesture would be coded at least as an incipient show and potentially, as a fully formed conventional show. Incipient gestures are those that are plausibly part of the developmental trajectory toward the emergence of the conventional gesture form. Moreover, Fiona showed persistence with her gesturing (indicative of intentional signaling) (12), moving the leaf closer to Sutherland and more into her line of sight until Sutherland clearly adjusted her head to follow the movement of the leaf. Although Sutherland dropped her gaze to the leaf when Fiona first extended her arm, this may not have been clear from Fiona’s perspective, and head direction could have been a more reliable indicator for her. Once Sutherland had clearly seen the leaf, Fiona ceased gesturing, suggesting that the goal of Fiona’s gesturing behavior was simply to get Sutherland to attend to the leaf.
However, there are two alternative explanations for the gesture, all of which the authors find implausible (my paraphrasing):
1). Fiona was trying to share the leaf (and/or any parasites on it) with her mother as food. This seems unlikely because Fiona did not surrender the leaf to her mother. Further, chimps at Ngogo don’t eat this species of leaf. In sixty-six other observations of chimps grooming leaves near other chimps, there were no cases in which the nearby chimp took or ate any part of the leaf.
2.) Fiona’s leaf play was meant to induce some other “dyadic social activity” like grooming or playing. But chimps already show, as we see in the first video, different gestures to initiate these activities, and Fiona’s display gesture was different from these. And in 58 other observations of leaf grooming involving 30 chimps, only 5 such behavior—none showing “declarative referential gesturing”—produced immediate social grooming or play. This is the case even though three quarters of all leaf grooming events got the attention of other chimps (this was absent in the one above, making Fiona produce the referential gesture). The authors conclude:
Overall, there were no consistent differences between the leaf groomer’s behavior before and after leaf grooming, with social behaviors (social grooming, play) being more frequent before than after. This indicates that leaf grooming is not reliably used imperatively to elicit grooming or play from a partner, making it unlikely that Fiona gestured to request such an outcome.
The upshot: In my view, Fiona was indeed calling attention to the leaf (as the author say, Fiona was “sharing attention for sharing’s sake”), though we don’t know why. The fact that this is the first time such a gesture has been observed despite chimps being observed for decades AG (“after Goodall”) also suggests that referential gesturing is not common in this species. Perhaps it occurs only under very special and specific conditions, but we’ll need a lot more observations to reach this conclusion.
However, if we do find that referential gesturing in chimps is part of their behavioral repertoire, it leads to one inference, an inference that was the subject of Darwin’s book The Expression of the Emotions in Man and Animals (1872). Darwin found (or thought he found) similarities in how humans and other species express emotions, leading him to conclude, as part of his Big Game Plan, that our emotional expressions evolve from precursors present in our common ancestors with other species, and that other living species have inherited expressions resembling ours from those ancestors.
In this case, it’s not really the expression of an emotion that Fiona shared with humans, but a referential gesture. But the implication is the same. As the authors say, the analogy to human behavior is critical here:
Several aspects of the Fiona–Sutherland interaction provide hints as to where such future research may find further examples of showing and other protodeclarative gestures in one of our closest living relatives. . . Additionally, Fiona was interacting with her mother, with whom she shared a close social bond. Our observation suggests that in highly specific social conditions, wild chimpanzees, like humans, may be motivated to communicate cooperatively and share interest and attention simply for the sake of sharing. If so, this raises the question of whether differences between humans and chimpanzees in the ability to engage in cooperative communication are quantitative rather than qualitative, with ramifications for our understanding of the evolution of human social cognition.
I presume, though, that animals like cats and dogs could be trained to respond to referential gestures. (They’re already trained to make them to humans, like pointer dogs assuming a stance pointing to human prey.) Has anybody trained of observed their pets respond to a referential gesture, like looking at something you’re pointing at rather than at your hand?
Today’s batch of bird photos, plus a primate and a stanchion, comes from Bernie Grossman, whose notes are indented. Click on the photos to enlarge them:
We took a guided tour in 2014 to Japan in winter to see resident and migrant birds, particularly the cranes. We traveled first to the area called the Japanese Alps, which is an east -west band north of Tokyo. The famous Snow Monkeys are found here (Tourist Trap). Then we went to the southernmost island (Kyushu) and the city, Kagoshima, where the Hooded and White-naped Cranes winter. The last stop was Hokkaido, which was having its worst winter in years. Most of the island except the eastern coast was blocked. The best birds here were the Red-crowned Cranes and White-tailed and Steller’s Sea Eagles. We missed the Blakiston’s Fish Owl, the world’s largest owl.
Eurasian Nuthatch(Sitta europaeca amurensis) This taxon is found in the Japanese Alps and south:
Japanese Macaque(Macaca fuscata) Also accompanied by a similarly furred member of genus Homo. The apes bath in artificial pools fed by nearby hot spring. The pools are located in a national park and required a long walk along an icy road:
Hooded Crane (Grus monacha) These and the next crane species migrate into southern Kyushu for the winter and feed in large numbers in agricultural fields. The local government established a crane feeding center where grain and corn is spread. This attracts thousands of cranes which are viewed from the visitors’ center:
White-naped Crane(Grus vipio) This species was the less abundant of the two at the center. Also present were three Sandhill Cranes (Grus canadensis) and two Common Cranes (Grus grus):
Japanese White-eye (Zosterops japonicus) We were surprised to see fruit trees in bloom is southern Kyushu in February. The White-eye was photographed in a flowering hedge in a farming area:
Red-crowned Crane(Grus japonensis) This is the national bird of Japan and is found in numbers near Kushiro in Hokkaido. They are large, graceful birds which we saw mostly at feeding stations where grain was spread on the snow. We saw others feeding in streams, etc. There is a famous bridge over a small stream that attracts large numbers of photographers with big 600mm prime lenses and other kit. The government built a second, parallel bridge strictly for photographers and safety. If it is cold enough (<20F), a fog forms above the warm water. The cameras have remote triggering and fast frame settings, so when a crane emerges from the mist and/or does its dance, the cameras are fired. It sounds like a whole machine gun squad shooting. I asked one guy how much time it takes to process all the pictures. He responded, “Who processes!” On a second trip five years later taken in the spring, we saw a few of the cranes in Hokkaido including a pair with two chicks:
Hawfinch(Coccothraustes coccothraustus) Photographed in snowy woods in the northeast peninsula of Hokkaido:
Brown-eared Bulbul (Hypispetes amaurotis amaurotis) The only bulbul in Japan and fairly widespread:
Ural Owl(Strix uralensis) A winter resident. This shot required a slog down a hill through deep snow to a tree with a big hole in the trunk. The owl was calmly sunning itself and giving great views:
White-tailed Eagle(Haliaeectus albicilla) While this species can be found in the whole of northern Eurasia, they are concentrated on the Notsuke Peninsula in northeastern. Hokkaido. This is a cold, windswept point of land used mostly by commercial fishermen. We found it empty and snow covered. These eagles were perched along the shore:
Steller’s Sea-eagle(Heliaeetus pelagicus) This is the wold’s largest eagle and is usually found along the northeastern edge of Asia (Manchuria and Russia). Some move south to Hokkaido in the winter. One was sitting on a power pole along the Notsuke road. We were able to approach fairly closely by very slowly walking toward it. It was huge with a magnificent beak:
Eurasian Jay (Garrulus glandarius brandtii) This taxon was seen in Hokkaido and has a dark eye. Another taxon, japonicus, has a pale eye. The species is seen across Eurasia.
Bunny Stanchion (Stanchion stanchicus bunni) These stanchions as well as others shaped like monkeys, raccoons, and others were seen all around Japan. They usually supported galvanized pipe.
Today’s batch of photos come from Costa Rica, and were taken by Fred Dyer. His notes and captions are indented, and you can enlarge the photos by clicking on them:
Some Photos from Costa Rica 10-20 July 2022
I recently traveled around Costa Rica with my family for about 10 days prior to a conference. Our itinerary included a day in the capital city of San Jose, a couple of days in the mountainous/volcanic region northwest of San Jose, and then several days along the central Pacific coast. Costa Rica is an amazing place, geologically, biologically, and culturally. Almost everything you see is beautiful. These photographs are a grab bag that don’t have much in common except that they were the ones that came out looking pretty good.
First, a few photos from near the town of La Fortuna and the Arenal volcano, including from a guided walk through a private rainforest reserve. On the walk we saw toucans, howler monkeys, army ants, leaf cutter ants and morpho butterflies, plus these (I welcome corrections on the species identifications):
Python Millipede (Nyssodesmus python). This one was about 8 cm long.
Eyelash pit viper (Bothriechis schlegelii), which gets its common name from the hairlike scales protruding over each eye. It is a small snake, but one of the most dangerous in Costa Rica.
Stingless bees (Apidae : Apinae : Meloponini: Perhaps Tetragonisca sp?) guarding their nest entrance tube. There are something like 60 species of stingless bees in Costa Rica. These guard bees were 4-5 mm in length. The colony is enclosed in a cavity so its size is hard to know, but some species have several thousand workers in each colony.
View of the Arenal Volcano from the north. This volcano began erupting violently in 1968 and continued until 2010. Vapors still issue from the peak, although this picture shows only clouds:
Golden-bellied Flycatchers (Myiodynastes hemichrysus) perching behind our rental house in El Castillo (south of Arenal):
From La Fortuna/Arenal we drove toward the Pacific coast, and stopped at a wildlife rescue center (Santuario Las Palmas) near the town of Cañas in Guanacaste province. The enclosures held rescued jaguars, pumas, ocelots, monkeys and several species of parrots. We also spotted some wildlife outside the enclosures:
Automeris metzlicaterpillar (larva of a Saturniid moth—in the same genus as the North American Io moth). This beauty was about 10 cm long
Same caterpillar after it moved onto a twig. The urticating spines supposedly produce a nasty venom. Here is what an adult Automeris metzli looks like. Whereas the larva relies upon aposematic signals and spines to deter potential predators from attacking, the adult is cryptic in the resting position, and exposes eyespots as a startle cue.
You can read more on Automerishere.
Black Ctenosaur (Ctenosaura similis), also known as the black spiny-tailed iguana, grazing at Las Palmas. These large lizards are extremely common along the Pacific slope:
On the coast our home base was the resort town of Manuel Antonio, which is next to the wonderful Manuel Antonio National Park.
Ponies for the tourists:
In Manuel Antonio National Park, stingless bees (species unknown) on a Heliconia sp.:
Also in the park, Panamanian white-faced capuchins (Capuchin imitator) engaged in a groomfest, while baby looks on. These were part of a larger group of a dozen or so monkeys in a grove of trees about 3 meters above the ground:
Same monkeys, still grooming.
Back in town, a Groove-billed Ani (Crotophaga sulcirostris) with some insect yumminess for its nestling(s). These are large birds (a bit bigger than a grackle) in the cuckoo family. They often nest communally but this seemed to be a single mated pair. The nest was in a tree across the street from our rental house in Manuel Antonio. Pictures of the nestling(s) and the other parent didn’t come out so great.
Playa Hermosa, a black-sand beach about an hour north of Manuel Antonio. This is a destination for expert surfers, and the surf was really intense the day we were there.
American Crocodiles (Crocodylus acutus) basking next to the Tárcoles River below the “Crocodile Bridge.” This is a tourist attraction on the main coastal highway (Route 34). The travel guidebook said that there is a population of 2000 or more crocs in this river and the nearby Carara National Park. Crocodiles often rest with their mouths open to dissipate heat.
Don’t forget to send your photos in! There’s a prize! (You get to show them off to a lot of people).
Today’s batch comes from Daniel Shoskes, whose captions and IDs are indented. Click on the photos to enlarge them.
It’s been a few years since my last submission so I thought I would share a few photos from a recent trip to Belize. Brown Iguana, Toucan (the national bird of Belize), Howler monkeys, nurse sharks and a Roseate Spoonbill. [JAC: not in order, but I trust you won’t be confused.]
Today I’ll show my own “wildlife” photos just for fun, but keep sending yours in. Click the pictures below to enlarge them.
Feeding wild cats at a nunnery in Mystras, Greece, 2002. I always carry a box of dry cat food in my backpack in places like this.
A rare bloom in Death Valley, California, 2005. I don’t know what the moth is, and I’m baffled about where the many pollinating insects come from in those very occasional wet years. They just appear from out of nowhere.
Me feeding a grape (with permission) to a ring-tailed lemur (Lemur catta) at the Duke Lemur Center, 2006. Note the baby clinging to its belly.
Cepea nemoralis snails on a fencepost, Dorset, England, 2006. The riot of colors and banding in this species was subject to a lot of investigation when I was in college, but evolutionary geneticists still don’t have an explanation for why the variation persists:
A butterfly (I don’t know the species) in the garden at Thomas Hardy’s boyhood home, 2006:
Snail and fly near Clouds Hill (T. E. Lawrence’s cottage), Wareham, Dorset, 2006:
Gooseneck barnacle, a rare and expensive delicacy. Galicia, Spain, 2006:
The one above was found on the rocks at low tide. Here are some for sale in the market. You eat the meat underneath the leather skin. It’s very good.
Me feeding a Texas longhorn on David Hillis’s and Jim Bull’s Double Helix ranch outside Austin, 2007:
Please send in your good photos, as the tank is depleting faster than I’d like. Thanks.
Today we have a potpourri of photos from various readers and contributors. Their captions are indented, and you can enlarge the photos by clicking on them.
The first photo is by Jamie Blilie:
Winter plumage American Goldfinch (Spinus tristis) in the middle of a snowstorm. Taken Dec 23, 2020, in a tree in our back yard, Minnesota. We have many winter resident birds. We have many feeders in our yard to help them through the winter (we feed much less in summer).
Reader Bryan found slugs making The Beast with Two Backs in Middlesex County, Massachusetts:
I saw this the other day (cool fall day in N. hemisphere).Reading a bit tells me it is gastropod copulation involving Spanish slugs, Arion vulgaris. It was satisfying to know I stumbled (figuratively!) on a fascinating biology topic.
From Thomas Czarny, sent September 8:
Yesterday an epic line storm coming across Lake Michigan slammed into the Traverse City, MI area causing widespread wind, rain and hail damage. Below is a sequence of photos of the advancing front as it swept inland from the Sleeping Bear Dunes National Shoreline. Only the first one is my photo, the rest are from friends and other local sources. At last report the Cherry Hut in Beulah is still intact.🍒
From Divy:
We went to the Ubud Monkey Forest in Bali a couple of years ago. If I remember correctly, this was a tourist conservation, owned by the local community. There were several Hindu temples within the forest which were closed-off to the public; only the monkeys could enter. I believe these were Balinese long-tailed macaques (Macaca fascicularis).
Reader Reese sent in some photos he got from a friend who tends ducks in a pond by his house. I’m going to show these photos to Honey.
From my friend John Williamson who feeds ducks and other wildlife on a resaca in Brownsville, Texas. I hope some of your pals are planning on wintering there. His house backs up to Town Resaca (which appears to be a body of water that goes nowhere) in Brownsville, not far from the Gladys Porter Zoo. I attach a few more photos so your ducks have a better idea of the winter spa awaiting them:
Note that he has built a duck-feeding platform (and also a Buddha platform).
Nutria (rodents also known as coypu; Myocaster coypus) also appreciate the duck corn. There also seem to be duck pellets:
