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.
I now have three batches plus some singletons, and so we’ll have semi-regular photos for a while, at least. Today’s batch of tidal invertebrate photos, and one video, comes from math professor Abby Thompson at UC Davis. Abby’s captions are indented, and you can enlarge the photos by clicking on them. The video is also hers.
April tidepools, and a mystery den.
Starting with a video of a Ctenophore, Pleurobrachia bachei (Pacific sea gooseberry, a ‘comb jelly’). All appearances to the contrary, this is in a different phylum (Ctenophora) from the “jellyfish” of my earlier post, which are in the phylum Cnidaria. The flashing lights are the cilia in the “combs” that run down the sides, used for locomotion. This one wasn’t moving very much, but I was surprised it was moving at all. I picked it up off the sand quite a way above the water line, and dumped it into a shallow pool to take a photo. It seemed to be recovering pretty well from what I thought was death. It’s about the size of a walnut.
Phoronis ijimai(tentative- the white things). This is a species of horseshoe worm, which lives in tubes. I haven’t seen this species before, and it was in an awkward spot, so it was hard to get a good photo. The photo below that is from a few years ago of a worm from the same family, so you can see their general shape better:
Lastly the mystery den. Our entire front yard seems to have been tunneled under, with at least three major entrances- this pair of holes is just one of them. The holes are large, about 10 inches across. We’re dreaming of badgers, would be very happy with foxes, and really hoping it’s not skunks (I love skunks, but not in the front yard). A wildlife cam is the next purchase:
Camera: Olympus TG-7. Thanks as usual to some experts on inaturalist.
Abby Thompson of UC Davis has sent in some pictures of California tidepool organisms, as well as a video. Abby’s captions are indented and you can enlarge her photos by clicking on them.
Late January-early March tidepools, plus an octopus.
Bryozoans:
Lepas anatifera (pelagic gooseneck barnacle). Usually found clinging to something drifting around in the open ocean (the “pelagic” part of their name), these were on a large log washed up on shore:
Intertidal zones, illustrated. A well-placed vertical rock face, like this one, exhibits the idea of the different intertidal “zones”, each of which has its own specific collection of inhabitants. You can see mussels and barnacles clustered at the top (in the “high intertidal”), exposed to the air as soon as the tide goes out even a little. There are smaller colonial anemones next, beneath them the orange and purple ochre stars, and below those, arriving at the low intertidal level, some giant green anemones. If you peer into the water under the open giant green anemone, you’ll see a crab, probably a rock crab. There’s some back and forth- there are a few giant green anemones pretty high up in this photo- but the general idea holds.
This reflects each animal’s differing tolerance for specific conditions- time out of the water as the tide goes out, harshness of wave actions, etc. The nudibranchs (next few pictures) are usually in the very low intertidal:
Doto amyra (nudibranch). Visible through the translucent skin on its back are lobules of the “ovotestis” (thanks inaturalist expert! ). From google AI: “Ovotestes in nudibranchs are specialized, hermaphroditic reproductive glands that produce both male (sperm) and female (oocytes/eggs) gametes simultaneously”:
More eggs, this time from a snail in the genus Amphissa. I like the pointy egg casings, like wizards’ hats:
And here’s an adult of the genus- almost certainly Amphissa versicolor, but it’s an unusual color (they’re usually shades of orange or brown/tan):
In honor of Ghost the octopus, and also because I’ve finally figured out how to include videos, below is a clip from 2021 of an East Pacific red octopus (Octopus rubescens), cruising around the rocks (out of the water!) at low tide. I’ve only seen one twice, probably because they’re too cleverly camouflaged (possibly just too clever) for me to spot. This guy was about the size of a human hand, a miniature compared to the 50 pound Ghost.
This morning I woke up to this email from the Aquarium of the Pacific (I suppose I’d signed up for communications a while back) announcing the death of Ghost, the universe’s best-known and most loved Giant Pacific Octopus (Enteroctopus dofleini):
The Aquarium is saddened by the loss of Ghost, the giant Pacific octopus who was beloved by staff, guests, and those who learned about her online. Ghost died on March 24 after entering senescence, the natural end-of-life process after laying eggs. The Aquarium announced Ghost’s senescence online in September 2025. Ghost was resting behind the scenes while animal care and veterinary staff provided her with extra support and care during her senescence.
For interviews, please call 562-833-1455 or reply to this email.
Best wishes,
Marilyn Padilla / Chelsea Quezada / Andreas Miguel
(562) 951-1684 / (562) 951-3197 / (562) 951-1678
Public Relations
Aquarium of the Pacific
I’ve posted about Ghost several times before, and when she went into senescence, after producing a batch of infertile eggs (there was no male in her tank), they took her off display. I kept watching for a death announcement, but in the absence of one, I assumed she’d crossed the Rainbow Bridge and they were going to keep her death quiet. So I was taken aback by the announcement above because I didn’t think it possible for an octopus to senesce for seven months. But I guess it is possible. I looked it up on Wikipedia, which said this (my bolding):
After reproduction, they enter senescence, which involves obvious changes in behavior and appearance, including a reduced appetite, retraction of skin around the eyes giving them a more pronounced appearance, increased activity in uncoordinated patterns, and white lesions all over the body. While the duration of this stage is variable, it typically lasts about one to two months. Despite active senescence primarily occurring over this period immediately following reproduction, research has shown that changes related to senescence may begin as early as the onset of reproductive behavior. In early stages of senescence, which begins as the octopus enters the stage of reproduction, hyper-sensitivity is noted where individuals overreact to both noxious and non-noxious touch. As they enter late senescence, insensitivity is observed along with the dramatic physical changes described above. Changes in sensitivity to touch are attributed to decreasing cellular density in nerve and epithelial cells as the nervous system degrades. Death is typically attributed to starvation, as the females have stopped hunting in order to protect their eggs; males often spend more time in the open, making them more likely to be preyed upon.
Ghost lived more than three times that long, probably because she was lovingly cared for by the Aquarium staff, as recounted in this story from ABC Eyewitness News 7.,which also confirms the demise of the beloved mollusc:
A beloved octopus at the Aquarium of the Pacific in Long Beach has died, officials announced Wednesday.
Back in September, aquarium officials announced that Ghost laid eggs and entered the last phase of her life cycle, known as senescence. She had been resting behind the scenes while being taken care of by aquarium staff during her senescence.
Ghost the octopus is spending her final days at the Aquarium of the Pacific caring for her eggs – even though they will never hatch.
“We are going to miss her. Ghost left a big impression on us and on so many people, even those beyond our Aquarium,” Nate Jaros, Aquarium of the Pacific vice president of animal care, said in a press release announcing her death. “She was spirited and very charismatic and loved to interact with our animal care staff. She was very engaged with the mazes and puzzles our staff created just for her. Ghost had a preference for interacting with her aquarist caregiver, sometimes preferring these interactions over eating. She was especially inquisitive when our staff members would dive in the habitat for maintenance.”
In her last days, care for Ghost included hand-prepped quality seafood, curated enrichment activities for her mind, and state-of-the art veterinary care.
Although senescence is part of the natural life cycle of a female octopus, aquarium officials noted her passing was a sad time for all.
“We hope part of her legacy is raising awareness about octopuses and inspiring people to care for and protect the ocean,” said Jaros.
Ghost arrived at Aquarium of the Pacific in May 2024 and only weighed about three pounds at the time. She grew to be over 50 pounds and was estimated to have been between two and four years old when she died.
In the wild, giant Pacific octopuses live up to five years. They spend their whole lives alone and only come together briefly to reproduce.
Here’s Ghost being weighed (a hefty 40 pounds) in happier days:
As a thought exercise, and maybe in a comment, think about why it’s adaptive for a female to waste away unto death when she could start eating and perhaps produce a second brood. Why would evolution favor senescence in a case like this? Notice in the announcement above that she was indeed eating as she approached death, but senescence involves more than just food deprivation: humans senescence and die too, even when they’re eating.
Sadly, the tank has run dry. To proffer some content today, I’ve dug into my personal photo bank and will post a few miscellaneous shots with brief captions. Click to enlarge the photos
Woman collecting land snails for dinner, São Tomé, 2004:
BBQ dinner at City Market, Luling, Texas, 2004. Brisket, sausage, and the trimmings (beans, potato salad, and the mandatory white bread):
Death Valley and a rare post-rain desert bloom, 2005. Where do the insects come from since these blooms occur only about once a decade? (If you can ID the lepidopteran, do so.)
Usually there is only saltbush and creosote growing on the land, but in a bloom all sorts of flowers emerge from dormant seeds:
A rare Jewish cowboy, photo in the Eastern California Museum in Independence. The last time I went the photo was gone and nobody knew about it or even remembered it. I’d kill to have it:
Doing flies, 2005. This is what I spent most of my time doing before I retired.
Flying onto a glacier at Denali (Mt. McKinley). They were dropping off two climbers in a four-seater bush plane, and I hitched a ride there and back. I got to sit next to the woman pilot. From Talkeetna, Alaska. The peak in the center is Denali.
After we landed on the snow-covered glacier, the pilot had to make a runway to take off from, going back and forth on the snow about ten times to pack it down:
The famous polymorphism of color and banding within the snail Cepaea nemoralis, studied intensively by evolutionary geneticists for years. Despite that work and subsequent population-genetic analysis, we still don’t understand the significance of the variation. For some reason the field was covered with snails; these were on a fencepost. Dorset, England, 2006:
The cottage where poet and author Thomas Hardy was born in 1840 and grew up. Upper Brockhampton, Dorset, 2006.
When Hardy became famous and wealthy, he moved to a house he designed (also in Dorset), Max Gate, where he lived from 1885 until he died in 1928. In the garden by the house are the burial sites of his beloved dogs and cats. Here are two graves of his cats, Snowdove and Kitsy; I was told that they were inscribed by Hardy himself, who had worked as a stonemason when younger, but I can’t vouch for that story:
A draft manuscript of the famous novel Tess of the d’Urbervilles in Hardy’s hand (taken at the local museum):
T. E. Lawrence‘s (1888-1935) final residence the cottage called Clouds Hill. He lived here after he gave up his fame as “Lawrence of Arabia” and served in the RAF under the pseudonym “T. E. Shaw” beginning in 1935, commuting back and forth to the airbase on his motorcycle. The cottage was very spartan, and had no electricity. As Wikipedia notes,
In a 1934 letter to Francis Rodd, Lawrence (who had changed his surname to Shaw) described his home thus:[5]
“The cottage has two rooms, one, upstairs, for music (a gramophone and records) and one downstairs for books. There is a bath in a demi-cupboard. For food one goes a mile, to Bovington (near the Tank Corps Depot) and at sleep time I take a great sleeping bag… and spread it on what seems the nicest floor… The cottage looks simple outside, and does no hurt to its setting which is twenty miles of broken heath and a river valley filled with rhododendrons run wild. I think everything, inside and outside my place, approaches perfection… Yours ever, T. E. Shaw”
Lawrence had an education in the classics, and is one of my heroes as he was both a man of action and a man of learning. Here’s the inscription in Greek over the door above: οὐ φροντὶς (“why worry”), taken from Hippoclides.
Lawrence’s bathtub and shaving mirror:
Lawrence died in a motorcycle crash on May 13, 1935, soon after leaving the RAF. Heading home on his motorcycle, he didn’t see two boys on bicycles ahead of him because of a dip in the road. Swerving to avoid them at the last moment, he crashed his bike, sustained a serious head injury, and died six days later. A study of his death by a neurosurgeon who tended the dying Lawrence eventually led to the use of helmets by motorcyclists.
The crash site is a km or two from Clouds Hill, and my friend and I scoured the road on foot looking for the crash site, now marked by a memorial (I saw no dip in the road). We finally found the stone:
Ironically, there had been a car crash at the site right before we found the memorial:
When he crashed, Lawrence was riding aBrough Superior SS100 motorcycle. Here’s a picture of him from Wikipedia riding one (clearly not the death vehicle) that he called “George V”. If you go to Clouds Hill, you’ll see several of his motorcycles in a small garage.
Lawrence on George V, Wikimedia Commons, author unknown
Among those who sent in photos in response to my self-abasing plea was UC Davis math professor Abby Thompson, who specializes in tide-pool invertebrates. We have some of those today; Abby’s captions and IDs are indented, and you can enlarge the photos by clicking on them.
Family Littorinidae (periwinkle) (tentative ID) This snail is decorated with bryozoans – here he’s upside down, and here. . . .
. . . he’s right side up, so you can see the bryozoans:
Tectura paleacea (surfgrass limpet), Surfgrass is about 1/8” wide. This tiny skinny limpet fits perfectly on it:
Genus Doryteuthis (squid) eggs- in a bunch on the beach:
Squid eggs close up, so you can see the eggs inside one sack:
An unusually colored Epiactis prolifera (brooding anemone). Its babies are nestled into its shoulders:
Strongylocentrotus purpuratus (Pacific purple sea urchin). As juveniles these are green, and I’d only seen juveniles here before. This was big enough to be turning its adult purple, though it still has lots of green spines:
This is the last batch I have, so please send in your good wildlife photos. I know some of you out there are hoarding them. Don’t make me beg!
Fortunately, UC Davis math professor Abby Thompson has sent some photos of life in tide pools. Abby’s captions are indented, and you can enlarge her photos by clicking on them.
The weather over New Year’s was stormy; most of these pictures were taken when the rain let up for a few hours. There are generally fewer creatures visible at this time of year in any case-—the big surge in intertidal species happens in the spring in Northern California. An exception was one particular species of nudibranch, Phidiana hiltoni, of which there were dozens for some reason.
Genus Heptacarpus (some kind of shrimp). Not a great photo, but the color is true, and if you look closely you can see she’s carrying eggs:
Superfamily Mytiloidea (some kind of mussel). Tidepools make you very aware of how much we don’t know. This mussel species moved into my local pools in 2022, and this ID is still the best I have for it:
Pollicipes polymerus (Gooseneck barnacle). The red “lips” on this cluster (common this time of year) I’ve read variously are because of the shade they’re in, the cool weather, high hemoglobin levels, or all of the above:
Today mathematician Abby Thompson from UC Davis graces us with tidepool pictures from California. Her captions and IDs are indented, and you can enlarge her photos by clicking on them.
A few more photos from November tidepools in Northern California:
Subfamily Syllinae (family Syllidae)I like the red eyes on the worms in this family:
Oligocottus snyderi (fluffy sculpin) This is one of the tidepool fish that gets transfixed by a flashlight:
A close-up of the fluffy sculpin’s eye:
There are two species of worms in this photo. One I’ve posted before is the feathery one, from the family Sabellidae. The other is possibly some species of ribbon worm. I like the photo because it looks kind-of balletic:
Aeolidia loui(nudibranch) Those two small black dots may be eye spots, I’m not sure. There are two much fainter spots further forward and farther apart which are also contenders. They have primitive eyes, not usually very visible, which are believed only to distinguish light and dark:
Fissurellidea bimaculata (Two-spotted keyhole limpet) The “keyhole” is the hole in the top of the animal. There’s a small shell surrounding the hole. The shell is always much smaller than the body in this species, but in this one the shell is entirely covered by the mantle:
The first picture was taken through a microscope on an iphone and the last was also with an iphone. For the rest I used an Olympus TG-7, in microscope mode, with a lot of extra lights. I got some help with IDs from inaturalist.
