Learning your letters: The basics of Morphology
© Photo – Richie Owens
The San are known for their persistence hunting methods where they run down the animal through the heat of the day. The secret is that we humans can sweat to avoid overheating, but that animals cannot and will eventually drop with heat exhaustion. Beyond sweating and running, this process is all about tracking and feet, both the barefoot or sandal clad feet of the San as they follow the feet of the animal that has left its story in the sand.
In the stifling midday heat of the Namibian bush veldt I followed the trackers. The San Bushmen never stop surprising me with their level and depth of understanding of their environment. It is their tracking skill that enables them to hunt; to locate their prey and single out an animal that might right for hunting.
Once the tracks have been located, they must be followed. At this point the trackers change mode. Their usual laughter and chattiness is replaced by silence and hand signals. They communicate with gestures and soft clicks. They crouch quietly and patiently over the tracks to discuss possible scenarios - how fresh are they, what age is this animal, what is doing, where might it be going? They imaginatively enter the mind of the animal and begin to see through its eyes. The animal has written its autobiography in the sand; its personal story. Now the trackers begin to read it.
© Photo – Ben McNutt
Learning to be a tracker is like learning to read again. To begin with you start with learning your letters, then you work on your phonetics, start to pronounce words, string together sentences and eventually you are reading whole chapters. Changing environment, from sat temperate to desert, is a bit like trying to learn a new language! This process is beautifully summed up by this passage in ‘Animal Tracks and Hunter Signs’ by Ernest Thompson Seaton, first written in 1958.
“No more important task has he [the young Indian] than his reading lesson. Not just twenty-six characters are to be learned in this exercise, but a thousand. Not clear straight print are these characters, but dim, washed out, crooked traces. Not indoors on a comfortable chair are the lessons, with a wise and patient teacher always near, but out in the forest, often alone, and in every kind of weather. There he slowly deciphers the letters and reads the sentences of the oldest writing on earth…the one universal script. I mean the tracks in the dust, the mud or the snow.”
The evolutionary story of feet is also the first place I begin with student who come to me to learn tracking skills, both here in the UK or overseas. They must learn basic foot morphology as well as how to read….
So, where to begin? I think the best place to start is learning that there are lots of different types of animal feet. These can loosely be grouped into three categories, dictated by what part of the foot strikes the ground first – the sole, the toes or the nails.
To understand the morphology we have to step back in time, to when the first fish left the primordial soup and crawled onto land, developing lungs and limbs on the way. At the end of each of those limbs of this original mammal, there was five digits.
“It is not the most intellectual of the species that survives; it is not the strongest that survives; but the species that survives is the one that is able best to adapt and adjust to the changing environment in which it finds itself”. – An excerpt from Leon C. Megginson’s speech interpreting the core ideas outlined in Darwin’s “On the Origin of Species”.
This primitive foot is still in existence (look at your own) and is known as a plantigrade (or sole walker) foot structure. Where the mammal lands on its heel pad and rolls onto the long thin ligament that lies directly beneath the skin on the sole of the foot, the plantar fascia. Insectivores, bears, weasels and apes all have this foot structure.
When examining toes as a tracker, for simplicity’s sake we number them, with the inner toe, usually the lowest toe being labeled as ‘Toe 1’ (this is also referred to as the hallux, thumb or big toe) and the outer toe (the little finger or pinky) as ‘Toe 5’. Always numbering from the inside out.
Toe 3 tends to be the longest toe, followed by toe 4, then toe 2, toe 5 and finally toe 1 – understanding which is the longest toe can aid in telling which foot a track is from.
As different mammalian feet have evolved, toes have started to slowly disappear, usually helping to increase the speed of that species of animal, as there is less time spent placing the heel on the ground, rolling along the base of the foot, onto the toes and then onto the nail tips, and finally away. Just like when you transition from a walk to a sprint, you go from placing the whole foot to just landing on your toes and the balls of your feet. Less contact time, usually means a faster pace.
To shortcut this, some species have evolved to walk on their toes only and are know as digitigrades (finger walkers). Where ‘toe one’ no longer makes a mark as it is migrating up the leg and the forefeet still retain the carpal ‘heel’ pad, way up the foot. Good examples of this are the canines and felines.
Through evolutionary progression; tired of being predated by swifter animals, some species have evolved to move even faster as their limbs have lengthened and so have their toes, so they now only place their nail tips on the ground. They are called unguligrades (nail walkers), like the deer and antelope species.
There has been a further reduction in toes, with toes 2 and 5 beginning to turn into small dewclaws further up the foot.
Going from the back of the foot forwards, we have toes 2 and 5, the dewclaws, then the heel pads (like the fleshy pads of a finger); then what we will refer to as the sole, which is essentially the underside of the nail (or subunguinis).
Following this logic, the next step in evolutionary foot structure takes us to the equine foot; where the members of the horse family have lost all their toes apart from toe 3 which has developed a large metacarpal bone (the cannon bone) which terminates in a large hoof, with the vestigial remains of toe 4 present as the splint bone. On soft substrate, the toe pad or ‘frog’ can be seen. From an evolutionary perspective, by rights the horse should be the fastest animal.
Where to next?… jet packs!
All words and illustrations by Ben Mcnutt. You can learn more about him here.