Tim writes: while walking on the Peak District moors this morning I came across some Star Jelly, which I have only seen once or twice before. I took this photograph on my phone but I thought it was too interesting to keep to myself. I hope you agree. So what is Star Jelly? Well it also goes by the names Astromyxin and Astral Jelly, and was once believed to be deposited on Earth during meteor showers. There is a Wikipedia entry for it and much of this information is from that source.
There have been reports of this mysterious substance for centuries. For example John of Gaddesden (1280-1361) mentions stella terrae (Latin for ‘star of the earth’ or ‘earth-star’) in his medical writings, describing it as “a certain mucilaginous substance lying upon the earth” and suggesting that it might be used to treat abscesses. A fourteenth-century Latin medical glossary has an entry for uligo, described as “a certain fatty substance emitted from the earth, that is commonly called ‘a star which has fallen'”. Similarly, an English-Latin dictionary from around 1440 has an entry for “sterre slyme” with the Latin equivalent given as assub (a rendering of Arabic ash-shuhub, also used in medieval Latin as a term for a “falling” or “shooting” star). The Oxford English Dictionary lists a large number of other names for the substance all associated with stars: star-fallen, star-falling, star-jelly, star-shot, star-slime, star-slough, star-slubber, and star-slutch. But not all of the early writers believed it came from the stars. For example, the great 18th century naturalist Thomas Pennant believed the material to be “something vomited up by birds or animals”.
Debate about its origins has raged until recent years. And it turns out that Thomas Pennant wasn’t far off the mark. In 1951 the New Naturalists’ volume on British Amphibians and Reptiles said “star jelly is most likely formed from the glands in the oviducts of frogs and toads. Birds and mammals will eat the animals but not the oviducts which, when they come into contact with moisture, swell and distort leaving a vast pile of jellylike substance sometimes also referred to as otter jelly”. Bizarrely an article in Nature in 2009 muddied the waters when an analysis failed to find any DNA. DNA forms the basis of all life on Earth so a jelly without a trace of DNA fuelled the idea of extra-terrestrial origins. But the mystery was finally laid to rest in the BBC programme Nature’s Weirdest Events, Series 4, episode 3, (14 January 2015) when Chris Packham showed a specimen of “star jelly” and had it sent to the Natural History Museum, London, for a DNA analysis by Dr. David Bass who confirmed it was from a frog. He also found some traces of magpie DNA on the jelly which may point to the predator of the frog. Though the Magpie could have poked around in the jelly later.
But November seems like an odd month to find this unfertilised spawn on the moors. Though my friend Nick Acheson (@themarshtit) tells me that star jelly can spend months in the guts of a heron before being vomited. Which might explain why this unfertilised spawn was on the moors in November. I cannot think which predator might have eaten a frog high on the Peak District Moors in November, though Fox and Buzzard are perhaps the most likely candidates.
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Hi Tim, we find this locally, usually from early in the New Year, with fertilised spawn in the pools by mid January. Never sure if the predator swallows everything and vomits this up, or just avoids swallowing this bit in the first place. I guess it makes sense for frogs to have the jelly ready to go before they hibernate as they want to get on with producing spawn asap when emerging later in winter or spring.
Many thanks Ian. A couple of people have mentioned to me that they find it quite frequently. I think you are right that they must have the jelly ready before hibernation as I am sure that jelly came from a recently predated frog (as opposed to lying in the guts of a heron for months). And I suppose it depends on the predator as to whether it is disgorged afterwards or avoided in the first place. I can’t imagine a Heron picking out the bits it didn’t like before eating.
Otters go up on the moors to hunt amphibians but usually early spring. We have found spraints and empty frog skins on the local moors here (Caton / Whit Moor in Bowland AONB) and know of others who have followed otters from water courses (Coniston and the sea around Mull) up onto the tops of moors where they dig out frogs / catch them coming out of hibernation. The frog skin is often inside out. I wonder if this is also left by otter after consuming a frog and this is why it has been known as otter jelly?
Many thanks for that suggestion Tim. I must admit I hadn’t considered Otter as the possible predator but it was near to three reservoirs and a healthy river system. I had a good look round and found about ten patches of jelly within about half a metre of each other, but could not find any trace of the frog.
Hi Tim – A good overview of the phenomenon known as Star Jelly. I’ve had a long time interest in this having come across on the fells of southern Cumbria, the Forest of Bowland, the West Pennine Moors when I lived up that way, and more recently on Fenns and Whixall Moss NNR where I find it frequently from autumn through the winter.
I recently, pretty much confirmed the origin of the substance when I took a couple of record shots of it after finding about 8 blobs of it around one area on Whixall Moss. I tend to take snapshots like this as a photo diary. It was only when I got back and uploaded the photos to my computer than I saw there were several undeveloped blobs of spawn on the bare peat nearby, pretty much confirming it’s amphibian and most likely Frog origin. I also have a pretty good idea what left them in this area as there are regularly a pair of Carrion Crows that hang around here.
For a long time I was sceptical about the amphibian hypothesis, given that I usually found this substance on acidic habitats, moorland or bog, and from autumn through winter. From other accounts it is most commonly found in the autumn/winter. It’s neither the place nor time of the year when you’d expect wandering Frogs to get eaten. For instance on Fenns and Whixall Moss NNR, whilst you do see Frogs and Toads on the Moss itself, they don’t spawn in the pools, probably because it is too acidic (typically pH 3.2-3.4), and often I find these blobs right in the middle of the Moss.
However, the other year I found some blobs on the top of a fence at the edge of the Moss, which pointed to it being deposited there by a bird, probably a Corvid or Buzzard as they are the most frequent users of this fence. On the Moss there are a lot of Crows, attracted by a Pheasant shoot at the edge of the Moss, as I see the Crows carrying off Maize cobs the shoot puts out to keep the Pheasants there, and the Moss is littered with husks of Maize cobs.
It is quite likely a variety of predators are responsible for depositing it. I think the only question being do they regurgitate it or just leave it when eating the Frog. I strongly suspect they regurgitate it as I often find it close to puddles on the main tracks the Crows drink from.
Whilst I can only speculate on why it is found in autumn and winter when you’d expect the Frogs would have gone into hibernation, I have a hypothesis which likely explains it. It’s fairly consistent with Occam’s razor as you only need to make minimum assumptions. The Crows can often be seen to be foraging in the peat. It’s quite likely, Corvids being intelligent, that they have learned to find where amphibians hibernate (maybe fissures in dried out peat) and winkle them out. My experience of finding hibernating Frogs is that often you will find several, or even quite a few crammed into the same spot. So if the Crows know where to look, where they find one, they will probably find more, encouraging them to actively search them out. This would be entirely consistent with how I find Star Jelly. Often where I find one blob, there will be several blobs all deposited in a small area. What is more, you don’t see any of a few weeks, then suddenly find patches. This would be consistent with a Crow finding small groups of hibernating Frogs. The Crows do a lot of foraging on the surface of the bog in the colder months, and you wonder what they are looking for as it’s not a good time of year for invertebrates, and there are no worms as it is too acidic for them.
Many thanks for such a detailed response Stephen. I am staggered that two people have ticked dislike as there is nothing in there to dislike. My photos used to regularly attract a couple of dislikes which I assumed were from people I had upset previously. But back to the Star Jelly, you have added a great deal of useful information. I wasn’t aware that frogs hibernated communally. And finding it on top of a fence post and next to drinking puddles suggest regurgitation. Good to know there are others out there who are as interested as me in Star Jelly.
Small heaps of white globular jelly with tiny black eggs were deposited by a small garden pond close to the River Wharfe in Otley on 27 and 29/11/2020 (quite warm damp nights). A trail camera set up overnight on 30th recorded visits by 2 cats, one waiting by the pond. The most likely explanation seemed to be cats ambushing frogs heading to the pond to hibernate or emerging to feed, then vomiting up the eggs and ovum jelly. We did wonder about otters or a heron, both nearby on the river but the pond was very close to the house.