Lightnews — Scholar-powered news

Maija Karala

@maijakarala.bsky.social

3.2K followers 470 following 410 posts

Illustrator, science writer and a bit of a crazy rat lady. Paleontology, biodiversity, animal behaviour.

Posts Media Videos Starter Packs

Pinned

Maija Karala @maijakarala.bsky.social · Feb 7

Our @arador-innovations.bsky.social newest project is up for preorder now, both in English and Finnish!

After our acclaimed The Mind of a Horse comes a new book: The Mind of a Dog. Science Meets Comics! It's cutting edge animal cognition science packaged into a comic book story.

Digital drawing of a coarse-haired puppy holding a book in their mouth with little teeth showing. The book has a blue-and-white cover with the words "Koiran mieli" (Finnish for "mind of a dog") and two playfully leaping dogs on it.

Kuva kirjasta nimeltä "Koiran mieli". Kirjan kansi on sinivalkoinen ja siinä on kaksi leikkisästi loikkaavaa koiraa, toinen keltainen labradorinnoutaja, toinen valkoinen sekarotuinen. Kuvan yläosassa on teksti: ennakkotilattavissa nyt - arador.info/koiranmieli

Image of a book titled "The Mind of a Dog" with a blue-and-white cover featuring two playfully leaping dogs, one a golden Labrador retriever, the other a white mixed breed dog. On the top of the image, there's a text: Pre-order now - arador.info/mindofdog

A sample page of an upcoming comic book "Mind of a Dog". It features a part of a story in which adult dogs come to visit and socialize with four puppies on their owner's yard. One of the dogs - a dachshund - is scared of the puppies, and the illustration details the body language of his fear and defensive aggression. He gets to stay outside the fence. The other dog - a white mixed breed dog - is scared of strange adult dogs and barks at them, but she's friendly to puppies. There is also an illustration detailing the body language of her calm and friendly face.

5 21 110

Maija Karala @maijakarala.bsky.social · 1d

Haha, not weird at all. It's because they are highly promiscuous: instead of fighting for the right to mate, male rats take turns, and the ones producing the most sperm are most likely to sire pups. You can see the same thing in chimps and especially bonobos.

Maija Karala @maijakarala.bsky.social · 1d

I think so. I've had almost all my rats from a breeder who avoids inbreeding. Not all of the rats are quite as mixed as Elmo, but none are extremely inbred either. In 8 years and more than 30 rats, I've seen just one diagnosed case of actual cancer. Plus a few benign but sadly inoperable tumors.

1 2

Maija Karala @maijakarala.bsky.social · 1d

Thank you! I really enjoy sharing this stuff. They're such fascinating little animals and much about them also applies to other animals, humans & biology in general.

1 2

Maija Karala @maijakarala.bsky.social · 1d

Thank you! All this stuff is so fascinating to me that I love sharing it with anyone who might listen.

Maija Karala @maijakarala.bsky.social · 1d

Elmo has a lovely personality. Though he's a bit more temperamental and sensitive than, say, Lumo and Taika, he's also active, human-oriented and very cuddly.

No matter how many rats I have, there are never two that are the same. Their lives are such short flickers, but each one bright and unique.

Photo of Elmo on my lap, sniffing my shirt while being loosely held by my hand. Next to him is Basil, a smaller brown rat.

2 2 12

Maija Karala @maijakarala.bsky.social · 1d

From a pet breeder point of view, this other extreme has both benefits and downsides. There's a good likelihood of healthy, long-lived animals.

On the other hand, variation in traits such as personality can be large and unpredictable. The pups don't necessarily much resemble their parents.

A photo of Elmo trying to pick a fight with Taika, a black and white variegated rat. Unlike Elmo, Taika has an established lineage where his gentle temperature was known fairly certainly before he was even born.

1 1 9

Maija Karala @maijakarala.bsky.social · 1d

Elmo, on the other hand, has a very mixed heritage. He came from a Finnish breeder, but his dad is from Poland and is grandmother from Sweden. Going back further in his family tree adds rats from several Finnish breeders, imports from other countries as well as a single wild rat. No inbreeding here!

Photo of Elmo looking cute, with some maple leaves.

1 8

Maija Karala @maijakarala.bsky.social · 1d

Though convenient, inbreeding can have a high price for the animal.

In addition to risk of hereditary diseases, inbreeding depression causes loss of vigor: inbred animals are often smaller, less fertile and less resistant to infection. They can also suffer from allergies or autoimmune disease.

Three-part growth photo series of Kukka, my rat from years ago. He was the product of a pairing of half siblings. Though a sweet and lovely pet, he was always a bit weedy, never grew to his father's size and didn't live to be very old. His father had another litter with an unrelated female rat, and the offspring from that litter grew to be much beefier and larger than these inbred ones - even though their mother was a tiny, dainty thing.

2 6

Maija Karala @maijakarala.bsky.social · 1d

Pet rats, just as other animals kept captivity, are often inbred. It’s partly simply because populations are small and it's hard to avoid the same animals popping up in pedigrees. But sometimes it's by design, when close relatives are bred together to produce desired traits.

Photo of a white female rat nursing a litter of pups, about three weeks old. They are a variety of different shades of white and beige, some with curly fur.

1 6

Maija Karala @maijakarala.bsky.social · 1d

Red and ruby eyes are common in pet rats. In my opinion, it has a significant impact on their quality of life, and I personally try to avoid supporting their breeding. They eventually go more or less blind. Though rats aren't very visually oriented, their eyes are not just for decoration either.

Photo of Jännä, my ruby-eyed rat from years ago. He's hiding inside my shirt, peeking out looking nervous. Jännä was one of the rats that are visibly bothered by the deterioration of their vision over time. He got startled easily and spent a lot of time nervously scanning by waving his head back and forth, trying to figure out what was happening.

Another photo of Jännä walking around near a window in bright daylight (but not direct sunlight). He's narrowing his eyes because the bright light hurts.

1 6

Maija Karala @maijakarala.bsky.social · 1d

Most rats with the Siamese colouration are red-eyed, because eyes are warmer than their extremities and little pigment can form in them.

Mysteriously, rats have a separate “black-eye” mutation that restores colour into their eyes, though nobody knows yet how it works. I'm really curious about that.

Photo of two creamy white Siamese rats resting side by side, one with black eyes, the other with red ones.

1 6

Maija Karala @maijakarala.bsky.social · 1d

His colour is called Siamese – the same you can see in cats. It's also an extremely rare type of albinism in humans.

One of the proteins involved in pigment synthesis is slightly abnormal and pigment is only properly formed in low temperatures – giving Elmo dark points on his extremities.

Photo of Elmo on my arm. He's a creamy white rat with clearly visible dark point on the top of his nose, where his skin is cooler than elsewhere. Dark hear also grows on his ears.

Photo of Elmo inspecting a pile of books on a nightstand. From this angle, the patch of dark brown fur on his butt is clearly visible. There, too, the temperature of his skin is lower than in the more central parts of his body.

1 5

Maija Karala @maijakarala.bsky.social · 1d

However, Elmo’s Dumbo mutation is not on the gene itself. It's on a regulatory sequence that determines when the gene is active during the embryotic formation of the head. This only causes a mild abnormality in the shape of the head and ears.
journals.biologists.com/dmm/article/...

Deletion of a conserved regulatory element required for Hmx1 expression in craniofacial mesenchyme in the dumbo rat: a newly identified cause of congenital ear malformation

SUMMARY. Hmx1 is a homeodomain transcription factor expressed in the developing eye, peripheral ganglia, and branchial arches of avian and mammalian embryos. Recent studies have identified a loss-of-f...

journals.biologists.com

1 7

Maija Karala @maijakarala.bsky.social · 1d

Elmo's ear shape is related to a gene called HMX1. It’s a homeobox gene – one of the basic blueprints of animals that determine where each body part goes and how many copies of them are built. These genes are highly conserved across the evolutionary tree, as mutations to them are usually fatal.

Comparison photos of the faces of two pet rats. The one on the left has "top ears", which are the wild-type, normal rodent ears, rounded in shape and high up on the head. Elmo, pictured on the right side, has weird, unevenly shaped and unusually large "Dumbo" ears. They are low on the sides of his head, sort of like human ears, giving him a peculiarly cute look.

A scientific schematic illustration of how HOX genes - a subset of homeobox genes - determine where the head and tail ends of an animal are, in both fruit flies and mammals such as humans and mice. The illustration is from the article "Embryology and bony malformations of the craniovertebral junction" published in the journal Child's Nervous System in 2010 by Dachling Pang and Dominic Nolan Paul Thompson. Link to the paper: https://www.researchgate.net/publication/49717129_Embryology_and_bony_malformations_of_the_craniovertebral_junction

1 8

Maija Karala @maijakarala.bsky.social · 1d

Pet rat update!
Today, I’d like to introduce Elmo, one of the six-month old teenagers. He’s not only very cute, but also has some interesting genetics – a homeobox mutation, temperature-dependent albinism, and a complex ancestry. Here's a thread on pet rat genetics.

A selfie of me, except my face is almost completely covered by the face of a rat sitting on my raised arm and looking curiously at the camera. The rat is so close he's out of focus. He's creamy white with a dark brown nose point like a siamese cat, and somewhat oddly shaped ears.

Photo of Elmo the rat being held in the air under his arms. He has an impressive set of whiskers pointing in every direction.

4 1 23

Reposted by Maija Karala

Jeanne Timmons @mostlymammoths.bsky.social · 2d

"Similar radiocarbon dates for woolly mammoth and woolly rhino fossils from the same sites imply the presence of both faunas during this period." 🦣🦏🦛

NEaar lab @neaarlab.bsky.social · 2d

Intriguing study just out in @currentbiology.bsky.social led by Patrick Arnold & Michi Hofreiter @unipotsdam.bsky.social showing hippos might have still been roaming central Europe in the last ice age www.sciencedirect.com/science/arti... 🧪🦛#quaternary

Ancient DNA and dating evidence for the dispersal of hippos into central Europe during the last glacial

Late Pleistocene hippo fossils (Hippopotamus amphibius) from Europe have generally been associated with the last interglacial period (Eemian, 129–115 …

https://www.sciencedirect.com/science/article/pii/S0960982225012059🧪🦛#quaternary

3 9

Maija Karala @maijakarala.bsky.social · 4d

Nähdään parin viikon päästä Kirjamessuilla!

Arador Innovations @arador-innovations.bsky.social · 4d

Uutuuskirja ”Koiran mieli. Tiedettä sarjakuvana” @helsinginkirjamessut

To 23.10. klo 17–17.30 messujen Tiedetorilla: Miten koira ajattelee ja tuntee?

La 25.10. ja su 26.10.: Kirjan tekijätiimi tavattavissa Aradorin osastolla 7g135 klo 13–15 ja 16–18.

#koirat #tietokirjat #sarjakuvat #kirjamessut

Maija Karala @maijakarala.bsky.social · 4d

Drepanosaurs have such character!

Drepanosaurus, a Late Triassic arboreal reptile not closely related to anything living today. #Sciart

Illustration of an angry-looking lizard-ish animal standing upright on two legs on a mossy branch. The animal is blue-green with orange eyes and very strong arms.

6 38 160

Maija Karala @maijakarala.bsky.social · 4d

Thank you, it's lovely to hear that!

Maija Karala @maijakarala.bsky.social · 4d

Much more than people usually realise! And also capable of deep affection. 🩷 But they are active animals that need to be able to do activities typical to their species. It's usually possible to arrange these even in a smaller apartment, but it takes a bit of thought and effort.

Maija Karala @maijakarala.bsky.social · 5d

I missed World Animal Day, but here in Finland, it's an entire theme week. This year, it's about the welfare of small furry pets: rodents and rabbits. They make amazing pets when treated right - but they are not the "easy" children's pets often thought.

Could also be #Rattober 1 - Friend-shaped rat

A warm-coloured illustration of a large Siamese rat laying on his back gently held by a human hand, looking relaxed. The rat is licking the human's thumb while the other fingers are scratching his shoulder.

2 4 26

Reposted by Maija Karala

KOJAMF🤘🖤🤘 @kojamf.bsky.social · 6d

Dr. Jane Goodall filmed an interview with Netflix in March 2025 that she understood would only be released after her death.

800 17K 38K

Maija Karala @maijakarala.bsky.social · 6d

Well, looking at this!

I went hunting for wild truffles and brought this truffle-scented tissue for the rats. Taika's first idea was to grab it and bring it to me.

Taika has such a keen interest in mushrooms I'm sure he would be an excellent searcher if I could take him into the woods safely.

Maija Karala @maijakarala.bsky.social · 6d

Sad news: the kakapo population is down to 237 after a female bird called Solstice died of an infection.

According to the Kakapo Recovery Facebook page, she had
• 8 clutches
• 24 eggs laid
• 13 fertile eggs
• 6 chicks hatched
• 4 living offspring
• 27 descendants

Illustration of a kakapo - a large, moss-green flightless parrot with an owl-like face - sitting on a person's arm with just the arm visible. It has a circular framing depicting little scribbles of ferns and conifer branches. Behind it is a light brown background with pale lineart of mossy tree trunks and branches of New Zealand's forests.

1 26 83

Reposted by Maija Karala

Professor Euan Ritchie @euanritchie.bsky.social · 9d

A lovely story about Dr Jane Goodall's career & legacy, from Rachel Fieldhouse & Mohana Basu, in @nature.com www.nature.com/articles/d41.... Includes some comments from me about how researchers _can also_ be advocates and science communicators, and still be taken seriously (I hope)!

Vale, Jane.

Jane Goodall’s legacy: three ways she changed science

The primatologist challenged what it meant to be a scientist.

www.nature.com

1 22 77