Dear Readers, I have written before about how intelligent I think herring gulls are, and how we underrate their brains at our peril. But a study of the birds by Franziska Feist at the University of Sussex has shown that they are even more attuned to human behaviour than we knew.
The experiment was all about crisps. Feist and her colleagues presented crisps in either blue or green packets to groups of herring gulls, and then sat down about 5 metres away. The observer then either just sat and watched, or pulled a packet of crisps out of their bag and started to eat them.
When the experimenter was eating crisps, the gulls approached the packets 49 percent of the time, compared to 19% when the observer was just sitting around. But when the observer was eating crisps(and this is the clincher for me), the birds pecked the packet which was the same colour as the one that the observer was eating from 95 percent of the time.
So, this appears to indicate that a) the food choices of this group of herring gulls can be influenced by what humans are eating and b) that it isn’t in this case just about the type of food, but that they even take the colour of the packaging into account, to make sure that they are eating ‘our’ food. I find this astonishing, and you can read the whole article here.
This increasing attunement to the way humans behave is probably coupled with the way that herring gulls have changed their habits, from being largely coastal to coming inland and feeding from landfill sites. They nest on flat roofs everywhere, and are often seen to be a menace, in spite of the fact that they are declining and are on the IUCNs Red List of endangered birds in the UK. We are fast becoming their main source of food, so no wonder they are paying more attention to the finest nuances of our behaviour. The effect of all that junk food on the gulls themselves would be interesting to monitor.
Incidentally, a 2019 study showed that gulls are much less likely to steal your chips if they think you are watching them – only 26 percent of a sample of gulls touched the food if they were being stared at, and they took 20 percent longer to approach than if the experimenter was busy doing something else. So if you don’t want to be ambushed and chipless, it pays to be diligent, as it does in most situations. I wonder if the rise of the smartphone could be correlated with the increased success of herring gulls stealing food? Now that would be an interesting study.
And here is one of my favourite short films, of a herring gull ‘puddling’ for worms and then announcing their presence with a most gratifying ‘long call’. Just look at that intelligent expression! These are extraordinary birds, well worth our attention.
Dear Readers, I hope you’ll forgive my second ‘science-y’ post in a row, but this report caught my attention today, and it has made me think about a possible hidden reason for the decline in numbers of many of our most familiar urban species, such as house sparrows and many pollinators. The study looked at the lungs of grey squirrels which lived in a number of London boroughs (Westminster, Greenwich, Haringey, and Richmond) and compared them with squirrels living in Surrey and Wales. The urban squirrels had a higher incidence of markers for lung disease, with those in Westminster showing the worst symptoms and those in leafy Richmond the least. In all, 13% of the urban squirrels sampled had diseases of the trachea, and 28% showed evidence of lung disease.
This rather begs the question of what air pollution is doing to the lungs of even more sensitive creatures, such as birds, which are notoriously sensitive to air-borne pollutants. Personally I think that the causes of urban wildlife loss are multifactorial, but it’s interesting to think of air-pollution as being another ingredient in the mix, alongside habitat degradation, lack of places to breed, noise and light pollution and the general increase in concrete and decrease in green space.
Also, we know that people living in the densest inner-city areas also have the highest incidence of asthma and other lung diseases, so the results aren’t that surprising. Previous papers have identified that other urban animals, including dogs and feral pigeons, also have higher levels of lung damage than their country cousins, and I especially feel for small dogs walking along the pavement and inhaling all those exhaust fumes which are pouring out at nose level. However, the authors of the study point out the need for longer-term studies that look at specific pollutants, so that action can be more targeted and so that we can go forward with better information.
Dear Readers, this week New Scientist has a collection of posts about cats so here are a few of the highlights…I’m also now studying domestication and selective breeding in my OU course, so there’s a nice synchronicity going on.
Cats and wheat were domesticated at about the same time, about 10,000 years ago. Presumably the wheat attracted mice, the mice attracted the cats, the humans got some pest control and everyone (except the mice) was happy. But clearly it went further than that – a grave in Cyprus that was about 9,500 years old contained a human and a cat. Was someone buried with their family pet? I only hope it was all consensual on the part of the feline. DNA studies have shown that the ancestors of all domestic cats came from the Eastern Mediterranean, which is also where the earliest evidence for agriculture is found.
Cats are probably not really domesticated – many scientists categorise them as ‘semi-domesticated’, on the basis that they do pretty well without humans around, though the local wildlife less so. As anyone who has worked with foster cats knows, there is a critical window in a kitten’s development for becoming socialised to being around humans – miss that, and you have a hissing spitting ball of fur with claws and teeth.
Cats know the sound of their owners voice, and react differently when they hear a stranger’s voice, even if both recordings are of people talking in that silly high-pitched baby tone that so many people (yes even me) sometimes adopt when talking to their pets.
However, good luck with getting them to come when you call them, unless you have something they want.
Cats approached someone more quickly if the human offered them a hand and spoke to them. as opposed to doing just one or the other. They seem to be attuned to a set of our behaviours, rather than just one thing.
Cats also get jealous, as discovered in a study that looked at the cat’s reactions to their owner stroking a cushion and a realistic toy cat. How they expressed this jealousy (i.e. by beating up the ‘cat’ or sitting with their back to their owner or pooping in their owner’s bed) wasn’t related, sadly.
In a study in 2017, scientist Kristen Vitale Shreve found that, when offered food, human interaction, a toy or a scent, human interaction came first, followed by food (a big surprise to me I must admit). She followed this up with a study in 2019, in which kittens aged 3 to 8 months were taken into a strange room and left alone for two minutes. When their owners returned, 64% of the kittens interacted with their owners and then went on to confidently explore the room. If you were a child psychologist you would probably think of this as showing secure attachment, and Vitale thinks that cats can form strong, happy bonds with their human caregivers.
Cats sadly don’t have very expressive faces, and this might be one reason why we think they’re aloof, unemotional creatures – they can’t do that ‘puppy dog eyebrow’ thing that dogs do when they’re trying to persuade their owners that they haven’t been fed for a week. But they do have a wide variety of ways to let their owners know whether they’re happy or not, and if you learn to read the signs it’s amazing what they’ll tell you.
Dear Readers, this is a rather interesting tale, and I am still not sure what the moral of the story is, so I will leave it to you to decide.
Back in 2012, PhD student Michael Skarvla was shopping in his local Walmart in Arkansas when he saw a gigantic insect sitting on the wall outside the entrance, minding its own business. So, as entomologists do, he picked it up, held it in his hand while he did his grocery shopping and took it home. At this point he thought it was an antlion, a fairly common insect, and so he killed it, preserved it and stuck it into his insect collection.
Antlion (Distoleon tetragrammicus) Photo by Entomart.
For those of you who would rather see your insects alive, I agree. There are arguments for specimen collecting (for one thing, it’s often the only way to tell different species apart, and often if you want to preserve a habitat, you have to know and be able to prove what’s living there). Whether this applies to the entrance to Arkansas Walmart, I’ll leave you to judge.
Fast forward to 2020, and Skarvla is teaching a course on insect identification by Zoom. He pulls out this insect and starts to explain that it’s an antlion, before falling silent in front of his students. He realises that what he’s looking at is in fact a much rarer insect – a giant lacewing (Polystoechotes punctata). You might be familiar with the green lacewing that sometimes pops up inside the house on a summer’s night, but this is a much bigger critter, with a wingspan of up to 6.5 cm.
Green lacewing (Chrysoperla carnea)
Giant lacewings had suddenly disappeared from the east coast of North America – one hadn’t been seen for more than 50 years, until Skarvla discovered his specimen. He suggests that there is a small population of the insects in the nearby Ozark mountains, and maybe in a number of other places, although whether they’re still there, eleven years after the Walmart specimen was found, is anyone’s guess. The reasons for their sudden decline are unknown, but it’s been suggested that light pollution, urban development and invasive species might all have played a part.
The species first arose way back in the Jurassic, and is part of a group known as the Neuroptera, or net-winged insects. They are all carnivorous, with the larvae being exceptionally voracious with enormous prey-sucking jaws.
Neuroptera wing preserved in Baltic amber (By Makarkin, Wedmann, & Weiterschan 2014 – Makarkin, Vladimir N., Wedmann, Sonja, & Weiterschan, Thomas. (2014, December 31). FIGURE 1 in First record of the family Ithonidae (Neuroptera) from Baltic amber. Zootaxa. Zenodo. http://doi.org/10.5281/zenodo.227659, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=104134457)
And so, this is how science proceeds – a chance discovery outside a suburban supermarket leads to the realisation that an insect that it was thought had been extinct in the area for over 50 years turns out to have been around all along. It just goes to show how much there is to discover in the seemingly unpromising habitats in our towns and cities. There is still so very much that we don’t know.
You can read the whole New Scientist article here.
Dear Readers, there were many things that maybe could have been predicted as climate change takes hold, but I’m not sure that I would have guessed that one of them would have been turtles being washed up on UK shores. But this has been a particularly bad year for strandings – in a normal year, according to the Marine Conservation Society (MCS), from four to six turtles would typically appear between November and February, but there have been fifteen so far. The leatherback turtle can regularly be seen in UK waters, and is cold adapted, but these are loggerheads and even a rare olive ridley turtle. What appears to be happening is that as storms increase in number and intensity, more and more animals are being plucked from their usual waters in the Caribbean and along the coast of North America, and are being dragged all the way to the south west of the UK, with some animals also travelling as far north as Anglesey.
Most of these turtles are juveniles who aren’t strong enough to fight the currents, and sadly of the fifteen who were stranded, nine were unable to survive the chilly waters and have died. The others were alive, and were taken to wildlife hospitals for rehabilitation – hopefully they’ll be able to be released into warmer waters to continue their lives. It does make me wonder, though, what other animals are going to turn up in the wrong places – after all, we’ve had a walrus in Scarborough, a black-browed albatross in the north east, an American robin in a suburban garden and a whole raft of other unexpected bird species. As the climate changes, and ‘extreme weather events’ become more common, we might be in for a whole lot of surprises.
Thor the walrus in Scarborough (Photo from The Scarborough News)
Dear Readers, following my article about Spock my childhood dog yesterday, I remembered this article from New Scientist, which suggests that dogs know far more about our intentions than we might realise.
48 pet dogs were filmed as they sat on one side of a transparent plastic screen, with a hole in it. A human being on the other side of the screen showed them a treat, and then either teased them by drawing it back when they went to take it, or ‘accidentally’ dropped it. All the dogs got all the treats after 30 seconds, but their behaviour in the meantime was fascinating.
Where the dogs were teased, they often backed away, sat down and refused to make eye contact. I imagine if they could have said ‘harrumph’ (or something stronger) they would have done.
When it looked as if the human was just being clumsy, they maintained eye contact, wagged their tails and stayed close to the screen.
This might not sound like much, but it implies that the dogs clearly knew the intentions of the humans, something which had previously only been proved with non-human primates – I’ve heard of many experiments/observations of animals such as crows understanding the thought processes of another member of their own species, but am not sure that I’ve come across one which demonstrates such an understanding of us and our funny little ways.
And in a delightful detail, the dogs confronted with a ‘clumsy’ human wagged their tails more on the right-hand side, which apparently shows that they are happy. It seems that they can forgive us for being hopeless, but are less tolerant of us being asshats, and well done them. We should all be forgiving of mistakes and general human-ness, and a bit less forgiving of cruelty.
Dear Readers, the Christmas and New Year issue of New Scientist is such a delight that I thought I’d share a few highlights with you over the next few days, after yesterday’s rather more pensive post. First up is the brussels sprout. Scientist Chris Pires has made it his mission to discover the ancestor of the plant, and this has led him to some very interesting places.
Brussels sprouts have the scientific name Brassica oleracea, but sadly so do fourteen other varieties of cabbage, including cauliflower, Savoy cabbage, kohl rabi and kale. So how did this diminutive little chap get his start? It was thought that the brussels sprout might have been first domesticated in the UK, but another theory pointed to the Mediterranean. After doing some genetic analysis, it turned out that the closest relative to these green Christmas ‘favourites’ (I use the word advisedly) was a weedy plant called Brassica cretica, which languishes on the sunny shores of the Aegean.
This ties up with the first recorded mention of the Brussels sprout, in Greek literature from about 2500 years ago. The botanist Theophrastus suggested using the vegetable to offset the results of too much alcohol, something which is apparently still believed in Southern Italy to this day. I have no idea if you eat the sprouts before or after the intoxicating event, but either could, I fear, lead to disaster.
To my delight, it appears that Greek legend has it that cabbages sprang up where Zeus’s sweat fell to the ground.
Still, the theory about the Aegean weedy cabbage relative remains to be proven because apparently some of the Brassica cretica that the scientists found could themselves be feral – in a dry, hostile environment I’m sure people would eat every plant that poked its head up and that wasn’t actively toxic, so I imagine there have been endless crossbreeding between the species, both natural and encouraged by people. Will we ever get to the bottom of the heredity of the Brussels sprout? Who knows. I am just holding onto the vision of Zeus raising his arms to heaven as a whole shower of round green cabbages cascades out of his armpits.
And with apologies in advance for the scatological subject of the next brief item, it appears that artificial intelligence can detect diarrhoea with up to 98% accuracy if you place an AI listening device in a toilet. It’s thought that this might be able to track outbreaks of diseases like cholera. It appears that some poor human had to listen to hundreds of recordings in order to work out if there was a problem with someone’s defecation or not, so that the AI could ‘learn’. Whenever I’m fed up at work, I’m going to remember that things could be worse.
You can read the whole article here, if you have the stomach for it.
Dear Readers, I don’t know what it is about birds, but much as I like them, they don’t always like me. As you may remember, I was chased by a goose when I visited a City Farm, and when I went for my first ever visit to South Africa, our jeep was hotly pursued by a male ostrich, which was a bit like being hunted down by a velociraptor. Gosh, those creatures can run! And they know all the short cuts! I remember our jeep bumping over potholes and careering through bushes. We’d stop, thinking we’d finally outrun Mr Ostrich, only to hear the telltale thumping of his feet as he accelerated towards us. As he was more than eight feet tall on his tippy-toes and had already given someone a nasty peck on the head, we were all semi-traumatised by the experience. For the rest of the trip, the sight of an irate hippo or a prowling lion didn’t bother us, but we’d all shriek at the sight of an ostrich. It feels a bit like the chicken’s revenge.
Anyhow, I was fascinated by this article in New Scientist this week, which is all about the neck of the ostrich. Large animals tend to have more problems with rapid temperature changes because they can’t lose heat quickly (if you all remember your surface area to volume from school biology lessons). Different creatures evolve different methods to deal with this, like the enormous flappy ears of the African elephant. For the ostrich, the key seems to be that their necks act as a radiator.
Herd of ostriches (Photo Two)
Erik Svensson, from Lund University, Sweden, spent five years taking infrared photographs of ostriches at a research farm in Klein Karoo, South Africa, and discovered that the ostrich’s neck acts as a ‘thermal window’, emitting heat when it’s too hot, and retaining it when it’s too cold, thus keeping the temperature of the head and brain stable. Our guide on our ostrich-embellished South Africa trip told us that the birds only have a brain the size of a walnut, and was very disparaging about them. However, as the ostrich had reduced a whole jeepload of English tourists to jabbering wrecks I think he might have underestimated them.
The research farm has three different subspecies of ostrich, one from Kenya, one from Zimbabwe and one from South Africa. Interestingly, the ones from Zimbabwe and South Africa, where there is more climatic variation, seem to be better at shifting the temperature of their necks. Furthermore, female ostriches who had a greater temperature difference between their necks and their heads laid more eggs in the following period than ostriches with a smaller difference, implying that the neck is a buffer for heat stress. After all, keeping our brains from frying is important for any species, hence the need for sunhats and for none of that ‘mad dogs and Englishman going out in the midday sun’ stuff.
Ostrich panting (Photo Three)
Ostriches also pant, and Ben Smits at Rhodes University in South Africa wonders if the hot blood from the neck is actually shunted upwards and then cooled when the animal opens its mouth, as happens with dogs (and humans).
Scientists speculate that as the climate gets warmer, the neck of the ostrich could get even longer – this appears to be a genetic adaptation, and so it can be passed on through the generations. It’s clearly beneficial for the ostrich, both in terms of survival and of reproductive success. I’m not sure exactly how I feel about an even taller ostrich than the one that we met, but maybe next time I’m planning visiting somewhere which has ostriches, I’ll take a tin hat (though that might just lead to my brain overheating).
The strawberry poison dart frog (Oophaga pumilio) (Photo One)
Dear Readers, as the frogs return to my pond I found myself curious about frogs in general, so off I went to New Scientist. First up, here is the strawberry poison dart frog. In the archipelago of Bocos del Toro, Panama, the frogs vary greatly in colour according to which island they live on, although they are all the same species. Wildlife photographer Paul Bertner headed off to the islands, accompanied by his Panamanian guide who had won one of the islands on a gameshow. It isn’t clear why the frogs on the different islands look so different – presumably the colours give them an advantage in each habitat, so my guess would be that there are slight variations in plant cover and predators. Sadly, some of the colour variants are already becoming rare, because there’s a market for them amongst exotic amphibian collectors. Leave the frogs alone, people! Amphibians and other exotic animals are extremely difficult to rear and breed in captivity, and I dread to think how many die because their conditions aren’t correct. I speak, sadly, from experience, having tried to keep reptiles and amphibians in my twenties. I soon realised that this is a very tricky area which requires specialised knowledge.
Still, here are some of the photos that Bertner captured of the wild frogs, and very pretty they are too. You would never guess from looking at them that they were the same species.
Strawberry Poison Dart Frog (Photo by Paul Bertner)
Strawberry poison dart frog (Photo by Paul Bertner)
You can see all the photos and read the article by Alice Klein here.
From rainbow frogs to fluorescent ones. Scientist Julián Faivovich has found that the polka-dot tree frog of the Amazon basin is the first one that glows in the dark. making it 30% brighter at twilight than other frogs. It’s known that many microorganisms fluoresce, and so do some fish and sea turtles – in other words, they have substances in their skin that absorb light at one wavelength, and emit it at a longer one. Faivovich believes that although this species is the first amphibian which has been proven to fluoresce, it’s unlikely to be the only one – there are 5000 species of frog, so for this to have evolved just once is very unlikely.
The fluorescence happens at a wavelength that the frog can see, and so it’s probably useful for signalling and for communication although, as with so much about frogs, it’s still a mystery.
Polka-dot tree frog (Hypsiboas punctatus) in daylight….(Photo Two)
…and when seen under ultraviolet light (Photo Three)
In other good news, a new species of frog discovered in a protected forest in India in 2019 is the only living member of a lineage that dates back millions of years. The starry dwarf frog (Astrobatrachus kurichiyana) is only two centimetres long with an orange stomach. Interestingly, the number of frog species identified in India has leapt from 200 to 400 species over the past few decades, which just goes to show what you can find when you look. You can read the whole article by Adam Vaughan here.
Starry Dwarf Frog (Photo by Seenapuram Palaniswamy Vijayakumar)
And finally, you may be aware that frog species all over the world are being decimated by chytrid disease, a fungal disease of amphibians. Frogs are widely seen as the ‘canaries in the coalmine’ by ecologists, due to their acute sensitivity to changes in their habitat. Many zoos and institutions have been in a race against time, taking whole frog populations into captivity to preserve them and breed them, with the hope that they will be able to be reintroduced into the wild when a cure for the fungal disease is found, and when their habitats are secure. So it was great to see that some populations of frogs do seem to be developing immunity to chytrid, provided that there are enough of them and their habitat is not too degraded.
The Sierra Nevada yellow-legged frog (Rana sierrae) lives in the mountainous regions of California, but its population has been in decline for years. This is partly due to the stocking of the rivers where it lives with non-native trout, who eat the frog’s tadpoles, but the frog really started to decline when chytrid hit in the 1970’s. By 2000 the frog had disappeared from 93% of its habitat, and was classified as endangered. However, the good news is that the frog appears to be bouncing back, with an annual population growth of 11%. Scientist Roland Knapp puts this down partly to the Park Service’s good sense, as they stopped stocking the river with trout in 1991. However, the frogs that have survived chytrid now appear to have some resistance to the fungus, allowing the population to recover. This has also been observed in the Stony Creek frog in Australia, which also appears to have developed resistance.
However, scientists are cautious – in areas with tiny, isolated populations, or where there is already significant habitat degradation, it will be a lot harder for the frogs to survive long enough to develop resistance. It seems that those dedicated frog conservationists battling to save these animals will be busy for quite a while yet.
You can read the whole article by Brian Owens here.
Sierra Nevada Yellow-Legged frog (Photo by Joel Sartore, National Geographic Photo Ark/Getty)
Dear Readers, there are some amazing articles in New Scientist this week. First up, scientist Darko Cotoras of the California Institute of Sciences in San Francisco has found that a tiny spider found only on Cocos Island, off the coast of Central America, can make three different types of web according to the circumstances in which it finds itself.
Wendilgarda galapagagensis makes ‘aerial’ webs high above ground, attached to nearby stems and leaves. Near to the ground it makes ‘land’ webs, with long horizontal strands attached to branches, and with vertical strands anchored to the ground. Over pools it makes ‘water’ webs, like the ones in the photo, with the vertical strands attached to the water surface itself.
Cotoras wondered if this meant that the spider was actually turning into three separate species. However, when the spiders were relocated, they often started to build webs in the style that was most suited to their new home. In other words, these tiny invertebrates are not limited to just one web (which seems to be the case with many spiders) but can adapt according to circumstances. This seems to me to contradict one theory, which is that island animals adapt to occupy a very specific niche and are hence threatened if things change.
Juvenile Brown Ghost Knifefish (Apteronatus leptorhynchus) (Photo by Guy L’Hereux)
Brown Ghost Knifefish are found in the rivers of Colombia, and have a surprisingly complicated social structure. They use electric discharges to find food in the silty water, and to communicate with one another, and until 2016 little was known about them. Then scientist Till Raab and his colleagues at the University of Tübingen in Germany found a group of more than 30 fish in an area only 9 metres square. However, Raab noticed that there was little fighting between the fish, and wanted to examine what was going on.
In captivity, it was found that when a fish was denied access to a shelter by a competitor, the fish responded by targeting the other fish with electric pulses, which gradually increased in discharge before falling back to normal. The subordinate fish seemed to be deliberately provoking the fish who had control of the shelter into chasing and biting it. Although this didn’t result in a change of ownership, it did seem to improve the social standing of the subordinate fish, and over time seems to have ‘evened out’ the relationships between the fish. One fish that made repeated ‘attacks’ on the dominant fish eventually ended up with control of the shelter (one imagines a weary fish deciding that control of a piece of tubing wasn’t worth all this aggro).
Of course, the mere fact of being in captivity will have an influence on behaviour in any animal. However, what this does seem to illustrate is that fish are as capable of weighing up the delicate nuances of social relationships as any mammal.
The Chinese Continental Scientific Drilling Project (Image by Qin Wang et al)
And finally, here is something truly incredible. Scientists Hailiang Dong at the China University of Geosciences and Li Huang at the Chinese Academy of Sciences have discovered bacterial cells from a 5.1 kilometre-deep borehole in Eastern China (the Chinese Continental Scientific Drilling Project or CCSD). Previously, the deepest known microbes on land were nematodes found 3.6 kilometres deep in a South African gold mine.
At this depth, temperatures are a staggering 137 degrees Centigrade, far above the accepted threshold of 122 degrees Centigrade. Scientists now believe that temperature might not be the only factor involved – the pressure, the physical nature of the rocks and the availability of water might also play a role.
Proving that the cells are alive will be another problem – organisms living at this depth often have an extremely low rate of metabolism because of the poor availability of nutrients. However, experiments with deep sea organisms have revealed that, if fed, they often ‘wake up’ with surprising enthusiasm. It will be interesting to see what approach is taken with these new microbes.
One reason that finds like these are so exciting is that it greatly increases the range of habitats on other planets where life might be possible. But for me, a second reason is that it demonstrates the extraordinary versatility of life. It gives me hope that, even if we screw things up irredeemably on the surface, we might not wipe out life completely. Of course, we won’t be here to see it if things go that wrong but maybe, in millions of year time, the next inhabitants of earth won’t be quite so feckless with the planet that they inherit.
