My family & other animals: what is it that makes Homo sapiens unique?

It's a curious thing, but I can't recall ever having come across a comprehensive assessment of what differentiates Homo sapiens from all other animals. Hence this post is a brief examination on what I have found out over the years. I originally thought of dividing it into three neat sections, but quickly discovered that this would be, as Richard Dawkins once put it, 'a gratuitously manufactured discontinuity in a continuous reality.' In fact, I found a reasonably smooth gradation between these segments:

1. Long-held differences now found to be false
2. Possibly distinctions - but with caveats
3. Uniquely human traits

Despite the carefully-observed, animal-centered stories of early civilisations - Aesop's fable of The Crow and the Pitcher springs to mind - the conventional wisdom until recently was that animals are primarily automatons and as such readily exploitable by humanity. Other animals were deemed vastly inferior to us by a question of kind, not just degree, with a complete lack of awareness of themselves as individuals.

The mirror test developed in 1970 has disproved that for a range of animals, from the great apes to elephants, dolphins to New Caledonian crows. Therefore, individuals of some species can differentiate themselves from their kin, leading to complex and fluid hierarchies within groups - and in the case of primates, some highly Machiavellian behaviour.

Man the tool-maker has been a stalwart example of humanity's uniqueness, but a wide range of animals in addition to the usual suspects (i.e. great apes, dolphins and Corvidae birds) are now known to make and use tools on a regular basis. Examples include sea otters, fish, elephants, and numerous bird species, the latter creating everything from fish bait to insect probes. Even octopuses are known to construct fences and shelters, such as stacking coconut shells - but then they do have eight ancillary brains in addition to the main one!

We recognise regional variations in human societies as the result of culture, but some animal species also have geographically-differentiated traits or tools that are the obvious equivalent. Chimpanzees are well known for their variety of techniques used in obtaining food or making tools. These skills are handed down through the generations, remaining different to those used in neighbouring groups.

Interestingly, farming has really only been adopted by the most humble of organisms, namely the social insects. Ants and termites farm aphids and fungi in their complex, air-conditioned cities that have more than a touch of Aldous Huxley's Brave New World about them; in a few species, the colonies may even largely consist of clones!

Although many animals construct nests, tunnels, dams, islets or mounds, these appear to serve purely functional purposes: there is no equivalent of the human architectural aesthetic. Octopus constructions aside, birds for example will always build a structure that resembles the same blueprint used by the rest of their kind.

Many species communicate by aural, gestural or pheremonal languages, but only humans can store information outside of the body and across generations living at different times. Bird song might sound pretty, but again, this appears to be a series of basic, hard-wired, communications. Conversely, humpback whale song may contain artistic values but we just don't know enough about it to judge it in this light.

Birds and monkeys are happy to hoard interesting objects, but there is little aesthetic sense in animals other than that required to identify a high-quality mate. In contrast, there is evidence to suggest that other species in the hominin line, such as Neanderthals and Homo erectus, created art in forms recognisable today, including geometric engravings and jewellery.

Some of our ancestor's earliest artworks are realistic representations, whereas when armed with a paint brush, captive chimps and elephants produce abstract work reminiscent of pre-school children. We should remember that only since the start of the Twentieth Century has abstract art become an acceptable form for professional artists.

Jane Goodall's research on the Gombe chimps shows that humans are not the only animal to fight and kill members of the same species for reasons other than predation or rivalry. Sustained group conflict may be on a smaller scale and have less rules than sanctioned warfare, but it still has enough similarity to our own violence to say that humanity is not its sole perpetrator. One interesting point is that although chimps have been known to use sharpened sticks to spear prey, they haven't as yet used their weapons on each other.

Chimpanzees again have been shown to empathise with other members of their group, for example after the death of a close relative. Altruism has also been observed in the wild, but research suggests there is frequently another motive involved as part of a long-term strategy. This is countered with the notion that humans are deemed able to offer support without the expectation of profit or gain in the future; then again, what percentage of such interactions are due to a profitless motivation is open to suggestion.

A tricky area is to speculate on the uniqueness of ritual to Homo sapiens. While we may have usurped the alpha male position in domesticated species such as dogs, their devotion and loyalty seems too far from deity worship to be a useful comparison; certainly the idea of organised religion has to be alien to all other species? Archaeological evidence shows what appears to be Neanderthal rituals centred on cave bears, as well as funereal rites, but the DNA evidence for interbreeding with modern humans doesn't give enough separation to allow religion to be seen as anything other than a human invention. What is probably true though is that we are the only species aware of our own mortality.

One area in which humans used to be deemed sole practitioners is abstract thought, but even here there is evidence that the great apes have some capability, albeit no greater than that of a pre-schooler. Common chimps and bonobos raised in captivity have learnt - in some cases by observation, rather than being directly taught - how to use sign language or lexigrams to represent objects and basic grammar. It's one thing to see a button with a banana on it and to learn that pressing it produces a banana, but to receive the same reward for pressing an abstract symbol shows a deeper understanding of relationship and causality.

A consideration of a potential future is also shared with birds of the Corvidae family, who are able to plan several steps ahead. Where humans are clearly far ahead is due to a gain in degree rather than just kind. Namely, we have the ability to consider numerous future paths and act accordingly; this level of sophistication and branch analysis appears to be uniquely human, allowing us to cogitate about possibilities in the future that might occur - or may never be possible. Both prose and poetic literature are likely to be uniquely human; at least until we can decipher humpback whale song.

Finally, there is science, possibly the greatest of human inventions. The multifarious aspects of the scientific endeavour, from tentative hypothesis to experimentation, advanced mathematics to working theory, are unlikely to be understood let alone attempted by any other species. The combination of creative and critical thinking, rigour and repetition, and objectivity and analysis require the most sophisticated object in the known universe, the human brain. That's not to say there aren't far more intelligent beings out there somewhere, but for now there is one clear activity that defines us as unique. And thank goodness it isn't war!

Avian Einsteins: are some bird species as clever as primates?

One of the strangest examples of animal behaviour I've ever seen in real life took place in my neighbourhood last year, with what for all intents and purposes appeared to be a vigil or wake. Half a dozen Common myna birds (Acridotheres tristis) were gathered in a circle around a dead or dying member of their species, making the occasional muted noise. Unfortunately I was rushing to get to work and didn't stop to take a photograph, which was a shame as the birds ignored me even when I passed within a few metres of them.

Even though the street was a cul-de-sac, I couldn't help thinking that sitting in the road was not the safest place for the birds to congregate, considering that they could have stayed close by on the grass verge; instead their proximity to the central, non-moving individual seemed to override their concerns for personal safety. 

Some biologists have suggested that this behaviour, mostly known from corvids (that is, the crow family) is due to the birds' instinctive need to advertise the area to others as particularly dangerous. Although there are plenty of cats in my neighbourhood this idea doesn't seem to make sense, at least in this particular instance. There were several trees that would have served as convenient perching locations for the myna birds, who weren't nearly as loud as they usually are.

Without getting too anthropomorphic about it, they were a lot less garrulous than normal, implying a sombre occasion. Far from providing warnings about the locality, the birds were extremely quiet for a gathering of this size; I should know, as myna birds are probably the third or fourth most common species in my garden and their routine screeches and squawks are far from subtle, to say the least. 

So is it possible that despite one of their number no longer moving or making sounds, its fellow birds understood that this inanimate object was one of their kind?  I've occasionally found dead birds of other species such as goldfinches, song thrushes and blackbirds in my garden and none have been the subject of similar behaviour. As an amateur scientist - or indeed anyone with curiosity might do - I researched the subject and found that crows are well known for gathering around bodies of the same species while magpies (another corvid) have even been reported as covering up dead fellows with twigs and the like. Are these reports all April Fool jokes or are some species of Aves unsung geniuses?

Further enquiry led me to discover that the corvid family, which includes ravens and jays, is the pinnacle of avian intelligence, closely followed by parrots. I initially thought that my observations of the myna bird, a member of the Sturnidae family, constituted something new, until I read a 2014 report from the School of Biological Sciences in Malaysia stating that laboratory testing proved them to be better at counting food items than House crows (Corvus splendens). In certain situations then, myna birds are up there with the brainiest of their kind.

In January this year I received another surprise on reading that the three most common avian raptors in northern Australia's tropical savannas - the Brown falcon (Falco berigora), the Black kite (Milvus migrans) and the Whistling kite (Haliastur sphenurus) - have been reported as deliberately spreading bush fires. It appears that after lightning has started a wild fire, the birds pick up burning twigs in their beaks or claws and drop them on untouched forest or grassland some tens of metres away. This then causes prey items such as lizards, snakes, rodents and amphibians to flee the new fire zone, only to be picked off by the waiting raptors.

Although birds of prey in North and South America, West African and Papua New Guinea are known to hunt on the edges of wild fires, the ingenuity of their Australian counterparts is without precedent.  What's more, they appear to have been using this behaviour for thousands of years, since it is clearly recorded in local Aboriginal legends concerning 'fire hawks'; only until now, white settlers have ignored the stories due to their implausibility.

A 2016 report by the U.S. National Academy of Sciences has uncovered biological evidence to support advanced avian intelligence. Although their brains are a lot smaller than mammals, especially primates, this is obviously due to the overall diminutive size of the animals themselves. The brain mass to body mass ratio of some bird families is far larger than expected for an animal of that size, approximating that of the most intelligent mammals.

Although bird brains have a somewhat different structure to mammalian brains, the corresponding higher-functioning regions are both comparatively large and have a neuron density double that of primate equivalents. Therefore it appears corvids and some other birds have undergone parallel evolution that has maximised their cognition.

Birds are good at far more than just adapting to new conditions and environments, with the most social (as opposed to solitary) species leading the way in problem solving and abstract thinking. Here are few more examples that prove their cognition can go far beyond basic instinct:

1. Self-recognition: Eurasian magpies (Pica pica) pass the mirror test, meaning they can recognise their reflection as themselves rather than as another member of their species. 
2. Tool usage: various birds use twigs and cactus spines to extract insects, much as chimpanzees insert sticks into termite mounds.  
3. Deception: Woodhouse's scrub jays (Aphelocoma woodhouseii) have been observed moving food caches to deceive onlookers and keep the food to themselves.
4. Planning: Crows have used multi-step planning in tests to retrieve progressively longer sticks with which to reach food. This ability isn't new either, since the 1st century Roman polymath Pliny the Elder observed corvids undertaking similar behaviour to that described in Aesop's fable The Crow and the Pitcher.
5. Exploiting artificial environments: The kea (Nestor notabilis), New Zealand's alpine parrot, has learnt to unzip rucksack pockets to obtain food. Despite being unlike anything in nature, some bird species understand man-made objects.

When I was a child, the term 'bird brain' was employed for derogatory purposes while 'talking' caged birds such as cockatiels, budgies and parakeets were thought of as just mimics without any understanding of what they were saying. This continuation of the Western tradition that humanity is the pinnacle of creation, far superior to all other lifeforms, is now under serious attack. Our prejudices have caused us to ignore the evidence right under our noses, but as per my post on animals that farm, we humans have very few unique traits left. Avian intelligence is undoubtedly different from ours, but perhaps less so than that of dolphins, whose watery environment means they are unlikely to ever be tool makers.

Another issue is that compared to say mammals, there is a far smaller variety of bird forms; even such specialised species as penguins, ostrich and kiwi don't stray far from the generic Aves design, meaning we tend to associate bird intelligence with the most ubiquitous - and comparatively slow-witted - urban species such as house sparrows and feral pigeons.

Beginning in the 1970s, researchers have explored the sometimes controversial notion that if the dinosaurs hadn't died out at the end of the Cretaceous, a small- to medium-sized carnivore such as Troodon would have eventually evolved into a reptile with human-level intelligence. Crows and their kind may not have a primate-sized brain, but these dinosaur descendants are evidently far superior to the dim stereotype we usually assign to them. They may be small, but clearly in this case, size doesn't seem to matter: our feathered friends are capable of far greater mental activity than their songs, squawks and screeches imply.