From Great Danes and Dogue de Bordeauxs to miniature Dachshunds and Chihuahuas, man’s best friend comes in a variety of shapes and sizes, so how can they recognise fellow dogs even when they all look so different?

Dogs come in a variety of different shapes and sizes, featuring Jess the black Labrador, Jewell the miniature Dachshund, Percy the Bichon Frise, Luna the Dogue de Bordeaux, Scratch the Jack Russell Terrier, and Spud the mixed-breed. (Engager’s own photos)

The Kennel Club recognises 211 different breeds of dogs but with different coats and mixed-breeds, there are by no means 211 dog-shaped moulds. Despite this, your dog can decipher between a Bichon Frise and a lamb instantly. This is in part due to their impressive sense of smell which they use to smell the hormones secreted by other dogs. Not only do they have a large nose cavity, which contains a folded surface covered by the sensing organ that is up to 23 times larger than in humans, they also have a vomeronasal organ in the roof of their mouth for detecting smells [1]. This means dogs can smell up to 10,000 times better than humans [1].

Seven domestic dog skulls on display in the Grant Museum (Accession number: Z2909)

Dogs’ ability to recognise different chemicals through their sense of smell has been used by humans to sniff out drugs, explosives and even illnesses such as cancer and diabetes. But is this the only sense dogs rely on to recognise other canines? A study from 2013 tested nine dogs’ ability to correctly identify other dogs from pictures [2]. The dogs were shown two images: one of a dog (from a set of 3000 pictures of different breeds, including mixed-breeds) and one of a non-dog animal, which included cats, cows, rabbits, birds, reptiles and even humans. On command, the dog participant had to correctly distinguish between the images and place their paw on the picture of the dog. All nine dogs successfully chose the images of the dogs over the images of non-dogs the required 10 times out of 12. The study concluded that dogs could “form a visual category of “dog pattern”” ([2] page 647); however, it did not allow the researchers “to determine which dog morphotypes or which species were easier to discriminate” ([2] page 648). As the dogs were successful at distinguishing between dogs and other animals from photographs alone, it is clear that they don’t solely rely on a sense of smell.

Hair curlers with a hunting dog on from the Petrie Museum (Accession number: UC8529)

Although varying highly in appearance, from the colour of their coat to the length of their snout, dogs use both their senses of smell and sight to identify others. Exactly which visual cues are required is still unknown. One thing we know for certain is, regardless of how they look, they’re all good dogs!

Bibliography

[1] Miklosi, A., (2018) “The Dog: A Natural History” Ivy Press, Brighton

[2] Autier-Derian, D., Deputte, B.L., Chalvet-Monfray, K., Coulon, M., and Mounier, L., (2013) “Visual discrimination of species in dogs (Canis familiaris)” Anim Cong, 16, pp 637-651.

Like many of us, Leonardo da Vinci, the great polymath, wrote “to-do” lists. However, in true Leonardo form, his lists did not contain typical mundane tasks such as ‘pick up milk’ or ‘post mum’s birthday card’ but instead provide a fascinating insight into the mind of the Renaissance great. The entries on Leonardo’s list include ‘obtain a skull’, ‘describe the tongue of the woodpecker’ and ‘describe the jaw of a crocodile’. In the spirit of the New Year, with the motivation of completing tasks and resolutions, this blog post aims to tick off one of Leonardo’s 500-year-old objectives.

To start with, let’s return to a previous blog post by UCL museums that discussed the differences between crocodiles and alligators. It includes the location (alligators are typically found in North and South America, whereas crocodiles are typically found everywhere else), how porous the skin is (alligators only have pores around their jaws, whereas crocodiles have them everywhere),  and also the shape of the jaw. The blog post states that the crocodile’s jaw is narrower than the alligators: it is more of a V shape whereas the alligator’s is more rounded at the end, like a U. The jaw is also straighter in an alligator than a crocodile and crocodiles have bottom teeth that extrude from the bottom lip. This is enough information if you are simply looking to identify your crocodiles from your alligators but, for curiosity’s sake, we will continue.

The skull of a crocodile. (Grant Museum, X1224)

Walter Isaacson’s biography of Leonardo mentions the inventor’s interest in crocodile jaws. Isaacson states that “a crocodile, unlike any mammal, has a second jaw joint, which spreads out the force when it snaps shut its mouth. That gives the crocodile the most forceful bite of any animal. It can exert 3,700 pounds per square inch of force, which is more than thirty times that of a human bite” [1]. According to Science Daily, crocodiles have likely retained this ability since the Mesozoic Era, when dinosaurs roamed the earth].

A rather humorous experiment involving “ten gigantic crocodiles” was described in an article in Scientific American published February 25^th 1882. The aim of the experiment was to calculate the strength of the muscles of the crocodile’s jaw, which they determined as 1540 lb, although noted that “this experiment was performed on a crocodile already weakened by cold and fatigue, its force when in its natural conditions of life must be enormous”. The text also mentions “how difficult it must be to manage such ferocious animals in a laboratory” and measures some of the crocodiles as ten feet long and 154 lb in weight! Leonardo was possibly interested in these creatures for their warfare potential. After all, he was hired as a military engineer and creatively designed weapons and armour.

Sketch of the experiment to determine the power of a crocodile’s jaw in Scientific American (Copyright: Universal History Archives, via Scientific American)

Although Leonardo has a bit of a reputation for not finishing his works (look at the Adoration of the Magi, the Battle of Anghiari, and Saint Jerome in the Wilderness to name a few), Leonardo did in fact complete this task. He wrote in one of his notebooks “[the crocodile] is found in the Nile, it has four feet and lives on land and in water. No other terrestrial creature but this is found to have no tongue, and it only bites by moving its upper jaw”. This actually isn’t entirely true. The crocodile does have a tongue – in fact, the female crocodile uses her tongue to help crack the eggshells of her young. There are also many scientific papers that discuss the tongue of a crocodile (for example, see [2]). Furthermore, ‘The British Cyclopaedia of Natural History’ published in 1837 mentions that the crocodile only moving its upper jaw was an “old belief” [3].

Leonardo’s inquisitive mind and thirst for knowledge is reflected on every page of his notebooks. He fills them almost entirely with his fervent list-keeping, avid note-taking, and intricate sketches. The child-like fascination with every aspect of the natural world is a quality that enabled him to become an expert in many areas of studies, including art, anatomy, optics, and geology.

As we enter the New Year, a time for reflections and new beginnings, we could all do with “being more Leonardo” and seeking the answers to life’s curiosities. What unconventional item will you add to your next “to-do” list?

References:

[1] Walter Isaacson, Leonardo da Vinci: The Biography (Simon & Schuster, 2017), 398.

[2] J.F. Putterill and J.T .Soley, “General morphology of the oral cavity of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768). II. The tongue,”The Onderstepoort Journal of Veterinary Research71.4 (2004): 263-77.

[3] Charles Frederick Partington, The British Cyclopaedia of Natural History (Orr & Smith, 1835), 550.

By Stacy Hackner

One of the most frequent questions I’m asked isn’t about history or osteology. It’s “can you tell me what that thing is?” Many objects in the UCL Museums don’t have explanatory labels, so it’s understandable that visitors don’t know. However, it’s usually the case that we don’t know either! In archaeology, a number of excavated items are recorded with detailed descriptions of size, weight, material, but no conclusion as to the purpose of the object. The Petrie houses a number of smooth pebbles from predynastic-era graves. When those people had the technology to make wheel-thrown pottery and intricately carved stone vessels, why be buried with a simple stone? The anthropological answer is that it served a ritualistic purpose; the humanistic answer is that somebody saw a smooth stone they liked, one that felt good to keep in the hand and rub, and it became important to them. I have stones that remained in coat pockets for years, getting smoother and smoother from my touch. It doesn’t necessarily have to be “totemic”. Other artifacts are confusing because they look like modern items. One visitor asked me about a clay object that looked like a cog.

UC18527. Image courtesy Petrie catalogue.

I had no idea what it was! We do have various sorts of cogs from ancient times, like waterwheels and the Antikythera mechanism, but in this case I thought I could solve the mystery quite easily. The object had a UC number, indicating its place in the Petrie catalogue. I looked it up on the web (the catalogue is open-access) and found out it’s actually an oil lamp: if you look closely, you can see traces of burning in the centre. The same goes for the Grant Museum’s catalogue – if you can find the specimen’s number, you can look up the name. Then it’s fun to Google the animal and see what it looked like with all its fur on – the tenrec is my favourite example. With only the skeleton it looks like any other small mammal, but when complete it’s like a cross between a hedgehog and a fiery caterpillar.

If you’d like to know what something is, please do ask! We may not know, but love to learn about all the amazing objects around us.

Recently I had a chat about tigers with a young visitor at the Grant Museum. As you might know, in early 2015 it was reported that India’s tiger population has increased by 30 per cent from 1,706 tigers in 2011 to 2,226 in 2014. This is fantastic news as the global tiger population is falling due to illegal wildlife trade. But the high death rates in tigers in captive wildlife conservation is a serious concern too and the visitor asked me what tigers in captivity die from. I decided to find out.

Among felines, that’s cats such as lion, tiger and leopard, lions have the highest death rates. Death rates are higher in male felines compared to female and cubs have greater risks of dying than adults: about half of all cubs don’t reach the age of 2 years.

A study in India shows that morbidity (diseases) in felines is a big problem and a common reason of death. According to the study, the most common reason of death in felines is respiratory conditions (23% of all deaths) (for example bacterial diseases that affect the lungs) followed by digestive conditions (19%). Many of the diseases kill felines because they easily spread between groups of animals and it’s difficult to separate infected and non-infected individuals.

Hiring more guards and protecting reserves helps stopping the illegal wildlife trade and increases the number of tigers. This is absolutely crucial but doesn’t prevent and stop deadly infections. To help tigers live longer better facilities and skills are needed to prevent, treat and control for these disease-related deaths.

Click here for information about the increased tiger population in India. For the cited mortality study, click here.

While working at the Grant museum of Zoology the other day, I encountered a lovely group of teenagers that started asking me questions about the museum. As we engagers do, I automatically started talking about my PhD project. I told them that I was working with stems cells and trying to build a neural tissue in the lab, to which they replied with a tilt of the head in sign of confusion. So I inevitably had to change my explanation and told them that I was trying to build a tiny part of a brain in the lab.

With a change of head tilting they replied with “Uh, that sounds cool” and “Are you going to create a Frankenstein?” To which I, being the bubble buster that I am, had to reply with, “Well, actually, Frankenstein was the scientist that created the monster”. So no, I am not going to create a scientist, or a monster, or a brain. I could see a tiny deception in their faces, so explained that neural tissue doesn’t necessarily mean that I’m building an entire brain, although it would be helpful to have two brains instead of one, especially when writing a thesis!!! But no, scientists have not been able to grow a full size brain. The closest that scientists have come, has been to grow a group of brain cells that self-assembled into an “organoid” that resembles some structures of a brain.

So how is that different from a brain? Good question, I am glad you asked avid reader. Even though the cells scientists have grown have developed into different kinds of brain cells and had some neural activity, the maturation and differentiation of different brain areas was not complete. The connections and systems that make us see or hear or control our movements were not there.

It is not enough to have brain cells arranged together; the information that runs through neurons has to have specific highways and an overall order in the soup of chemicals and cells that is our brain. Besides all the intricate and delicate organization cells need to have, they also need nutrients and oxygen or in other words, blood vessels, little tiny ones and big chunky ones, to reach every cell so that they can survive and function. Yes, there are interesting advances into knowing how the brain works and how cells develop into a brain, but we are not there yet.

So the answer to “Can we build a brain in the lab?” is no, not right now. So contrary to what may have been on the news, lets just say that we can grow brain cells and keep them alive; we can make them interact with each other and grow groups that self-assemble, but we are years away from actually growing a fully functional brain. And in order to have a ”functioning” brain it would need to have eyes and ears and muscles and all of the systems that connect to it (basically a body) in order to be functional. Otherwise it would not have any input and would not be able to process information.

Many of the guys that I was talking to in the museum where relieved when I explained this to them, fearing that maybe science has come too far. Has it? I don’t know, but I will leave you with this question: Do you think it would be a good idea to build a brain in a lab?

Infographic from livescience.com:

This was the first question I was asked on the first day in my new role as a Student Engager in the Petrie Museum. The visitor in the Petrie came up with this when he was looking at some of the sandals – of different sizes – which have survived and are displayed in the museum’s collection. One sandal appeared to me to be around a modern-day size 9 or 10, so I guessed that those living in ancient Egypt ranged in similar stature to ourselves. I then directed the visitor towards some of the head rests in the collection, which, in what might be deemed a very ‘unscientific’ way, we also made some guesses about the size of ancient Egyptians, although we wondered whether we were looking at objects made for adults or children.

© Petrie Museum.

It seems that our guesses were not too far from some archaeological findings. In doing some research I learned that in under 2000 years the Egyptian population changed from being ‘an egalitarian hunter-gatherer/pastoral population to a highly ranked agricultural hierarchy with the pharaoh as the divine ruler’. One study suggested that from the Predynastic period (5000 BCE) until the start of the Dynastic period (3100 BCE) the stature of Egyptians increased, which was followed later by a decline (up to 1800 BCE). They put this down to an intensification in agricultural production which meant that access to food was more reliable, but they also suggested that it reflected the beginnings of social ranking. The decline in stature in the Dynastic period was the result of even greater ‘social complexity’, when there was greater difference in access to food and healthcare: essentially, the gap between the rich and the poor had widened.

Head rest with hieroglyphics. © Petrie Museum.

Nevertheless, over this whole period they found that the mean height (of their sample of 150 skeletons) was 157.5cm (or 5ft 2in) for women and 167.9cm (or 5ft 6in) for men, quite like today. What is quite different is that compared with the average difference of 12-13cm between men and women found in modern populations, in ancient Egypt it was only 10.4cm. This came as a surprise to the researchers, as men in ancient Egypt were thought to have benefitted more (than would be so today) from preferential access to food and healthcare. But their findings probably reflect the fact that the status of women in ancient Egypt was relatively high compared to other ancient societies.

Like today, there are many variables which would have determined the height of an ancient Egyptian. First off, like modern-day England, Egypt was an ethnically diverse and cosmopolitan society where body shapes and sizes of all kinds would have been found: there was no single build, nor hair or skin colour. And also quite like today, the wealth and social status of an individual played a part in determining their physique (although in twenty-first century England being overweight is more often linked to deprivation rather than wealth). All through human history we can see multiple factors – from disease, social status, access to food and cultural aesthetics (to name a few) – determining our physique. As we continue to ponder the ideal, healthy body-type in our own society, I’m sure we’ll continue to look back and ask questions about our predecessors.

For the cited archaeological study, click here.