Hedgehogs can hear sounds at 85,000 Hertz, over 4x our max frequency.
I was on a hike this week and took a a photo of a “fuzzy plant” thinking it was lamb’s ear or something… it was California Milkweed! so, this week I learned what California Milkweed looks like and am so happy to have seen it on the trail.
Depends on where they’re at. Beavers in Europe and North America are generally very beneficial. Beavers introduced as an invasive species in Patagonia contribute to deforestation and habitat loss because the trees in that area are slow to grow, unlike the trees in their native habitats. They cannot re-establish themselves after being cut down, and the beavers leave behind ‘ghost forests’ of dead trees.
That’s so cool! They are really pretty! Welcome to the forum!
I have just watched a superb documentary on BBC 4 tonight called The Birds, about a retired wildlife cameraman filming the interactions between wading birds and peregrines on the Norfolk coast. But the lifelong learning part was his assertion that the intricate pattern of pools in mudflats is due to the tiny but super-abundant snail Hydrobia ulvae eating the diatoms on sand grains, which makes the sand grains less sticky and more mobile. Are there any saltmarsh ecologists here who can verify that please?
Fair point; I really should have said “beavers in areas to which they are native” to be precise. In my defense, the article didn’t mention beavers as an introduced, non-native species, but we all know (or all should know, anyway) that introducing a novel species into an area that has no evolutionary checks on it is almost always a Bad Idea.
(Ever since finding out that European Starlings are decreasing in the UK, I’ve wondered if there was any tway that we could send them some back.) 
I found a really good example observation from another user on iNat that shows what the ghost forests look like after the beavers move in: https://www.inaturalist.org/observations/338575885
Despite our knowledge of the effects of invasive species, we’re not very good at correcting those past mistakes. The damage continues. And unfortunately, there are still plenty of people who don’t understand the harm they cause. I’ve had conversations with people even on this forum who just didn’t understand how a species that was beneficial in one place could pose a serious threat to the ecosystem elsewhere. More importantly, they didn’t seem to grasp the role of humans in spreading invasive species and how easy it is to lose control of an introduced population.
I saw an Indian Silverbill in the birdbath I’ve kept and noticed that its upper mandible/beak was much longer than usual. Turns out, when these silverbills eat a lot of soft food (which is not a part of their ideal diet) their beaks don’t wear down in the same way they do when they eat nuts. This is one of the reasons, and also AKD - which stands for Avian Keratin Disorder. Crazy stuff! I’m going to have to keep an eye out for the same individual.
I love squirrels but they do have a very dark side… they have their own version of dog eats dog.
Frogs shed their skins every week or two. We have lots of green tree frogs here and I have never found a skin. Because they eat them!
There was a thread about lichens recently, which sent me on a learning dive and where I ended up was… water bears / Tardigrada!
I very much want to see one though I wonder if I will be able to, as there do not seem to be any Observations of them near here and a microscope is not really accessible to me at this time.
But I really, really enjoy the idea of these quite tiny, multi legged sturdy, hardy beings living quietly in the lichens.
Also after being frozen, or heated, or in space. They are ridiculously durable.
There is a non profit search engine, Ecosia , dedicated to native habitat restoration primarily through planting native trees.
Oh, they’re much too beautiful to have such an unflattering collective name.
I hereby propose a new one: a “bouquet” of Roseate spoonbills - which I would love to see!
Oak trees will delay opening their spring leaves, by up to three days, if they were heavily fed on by caterpillars the previous year.
Interesting! I guess this counts as me learning something this week.
While the paper doesn’t pinpoint the exact mechanism, maybe the tree monitors daylength and temperature to determine the timing, and uses hormones (based on caterpillar herbivory) to delay budburst.
This week I learned in depth how the kelp reproductive cycle works. I didn’t know that spores do not become the adult plant, they only have half of the adult chromosomes and the spores job is to create the eggs/sperm.
I just learned that ice worms exist. Tim posted:
Potworms are in the family Enchytraeidae, which contains the genus Mesenchytraeus, which are known as ice worms!
“When ice worms are exposed to temperatures as modest as 5 °C (41 °F), their membrane structures disassociate and fall apart (i.e., “melt”) causing the worm itself to liquefy.”
Background: I was reading about this fascinating fluke (trematode):
After this fluke gets eaten by a snail, it makes its way into the snail’s eyestalks. It makes the eyestalks look like crawling caterpillars (video). This tricks birds into eating the snail, which is what the fluke wants, so it can finish its life cycle inside the bird.
What I learned: While reading up on that, I discovered that another fluke, Haplorchis pumilio, was found in 2024 to have a soldier caste, just like ants, bees and termites! Haplorchis pumilio can infect humans!