THE HORSE AND ITS' EVOLUTION
by Sue Tanzer
Adaptation to Habitat
Equus caballus, our present day horse, has been in a similar form for approximately 2 million years. His evolution began some 55 million years ago as a small mammal with five toes, called Hyracotherium, also known as Eohippus.
The evolution of the horse has been accurately documented as a complete fossil history has been discovered over the years. The evolution is closely tied to the earth's' climatic changes, making it necessary for the horse to adapt to survive in a changing environment. During his evolution the position of the great land masses of the world have changed enormously, to the extent of some breaking apart and others colliding. Climatic changes have been extensive, wiping out many other species.
The horse has therefore had to make the following changes to survive:
Increase in body size,
Development and specialisation of the brain,
Decrease in number of toes,
Loss of toe pad and development of hooves,
Lengthening of limbs in comparison to body size,
Fusion of lower limb bones,
Development of loco-motor systems to increase efficiency of movement.
These developments have given the horse the edge in the race for survival. They allow a relatively large animal to be fast for its' size and weight. Cutting down the number of predators able to kill it.
Other traits that enabled the horse to efficiently exploit the large grasslands which began to appear 50 million years ago were:
Development of high crowned teeth with a large surface grinding area
Increase in muzzle length, allowing more teeth
Development of hind gut fermentation
Brain development allowing more selective grazing
Ancestor of all modern day herbivore mammals was an order called 'CONDYLARTHS', these primitive mammals were in existence between 65 and 70 million years ago. They had five toes on each foot and a fine set of teeth, consisting of 6 incisors, 2 canines, 8 pre-molars and 6 molars, the maximum number found in any mammal. During the next 10 million years descent became more specialised in the form of the horse's proved ancestors:
The main evolutionary stages of the horse to the present day are as follows:
Hyracotherium 60 million years ago
Mesohippus 40 million years ago
Merychippus 25 million years ago
Pliohippus 5 million years ago
Equus 2.5 to 3 million years ago
Hyracotherium was a small creature, some 0.5 meters high, with an arched back, four hoofed toes and could probably trot and canter. He was a browser, living on small shoots and leaves of trees, of a higher quality than grass, these foodstuffs were abundant and Hyracotherium thrived. His fossil specimens have been found in both Eurasia and North America.
However, over the next few million years climatic changes meant that Hyracotherium died out in Eurasia while remaining in North America where he gradually evolved into Mesohippus over the next 10 million years.
Further climatic cooling began around 22 million years ago, lasting until 5 million years ago, when an icecap appeared over the South Pole. This caused sea levels to recede and allowed a land bridge along what is now the Bering Straits between North America and Siberia, once again allowing migration into Eurasia. Browsing horses continued to evolve in North America due to the vegetation but the horses that migrated to Eurasia became true grazing horses, due to the habitat of plains.
These grazing horses could exist because they had high crowned teeth, resisting the harder wear imposed by grazing rather then browsing. Another adaptation to survival on the plains was the lateralization of their eyes, allowing a far wider field of view to spot predators. Another development was sustained flight in a straight line, horses are not made to switch direction quickly, as do many other species living on the plains, but simply to outrun a predator.
Necessity for speed fused the lower bones of the leg together, giving added strength. Gradually the need for more than one toe disappeared and around 4 to 5 million years ago the horse became one toed. The oldest recognisable fossil of Equus was found in North America and is 3 million years old, within 300,000 years there is evidence of Equus in other parts of the world.
Much debate goes on about the differences of modern horses and their origins, i.e. Exmoor Pony and Arab, Prezwalski's horse and Zebra, all definite and vastly different types, but it seems to be the consensus of opinion that there is no single line of descent for all the modern equids. These are believed to have come from a number of subspecies. It appears that the modern horse Equus caballus, diverged from other modern days equids, i.e.. Zebra and Ass, some 1.5 million years ago. Domestication may have occurred and then spread around the globe with migrants domesticating the local population.
by Sue Tanzer
Behavioural evolution was closely linked to physical evolution by necessity of survival, therefore those of the population best able to adapt to changes in their environment lived the longest and left most descendants, gradually building a population best suited to survive. Those unable to adapt died out naturally, their life spans much shorter they left few descendants so their lines died out. This is known as natural selection and occurs in all feral populations. When man interferes and creates artificial, 'sheltered' breeding circumstances then many individuals are able to breed who would not have done so in a wild state.
As we have seen, the horse evolved from a pig like animal some 65 million years ago to the horse as we know it today some 1.5 to 2 million years ago. The main physical differences are the length of neck, length of legs and decrease from five toes to one, plus a general increase in size.
The landscape changed over this time, hence the necessity of the physical changes for survival. As the forests and swamps gave way to more open areas the horse, or his ancestor, needed to see around him for greater distances to be aware of predators and have a chance of escape. His neck increased in length. As the open areas became larger, he needed a greater range of vision so his eyes gradually moved to the sides of his head, giving almost all-round vision. He needed to run faster to escape predators so his legs increased in length in addition to gradual fusion of the lower limb bones to give added strength.
We have 2 variants of evolution:
Did horses legs become longer to enable them to escape?
Did the individuals with slightly longer legs manage to escape and therefore to breed so left descendants, also with longer legs thus carrying on the trait?
We can see the gradual development of a swift, far sighted animal that survived by running away. Hence we have our modern day horse, who is naturally fast for his size, is by nature nervous and a flight animal.
INSTINCTS INFLUENCING BEHAVIOUR
by Sue Tanzer
Alertness, Flight, Safety in numbers, Freedom of feet, No predators on back
The horse's natural nervousness makes him very wary. He knows he has no real form of defence except flight. A cornered horse will lash out with hind feet, forefeet or teeth under extreme provocation but he would prefer to flee. Instinct tells him to run away from whatever he considers a threat. Because of this instinct to flee, it is very important to the horse to keep his feet free. If one of his feet is trapped or held, he cannot run away. Reluctance to step into mud or water, where the depth cannot be judged, therefore the safety of the feet, is usually down to this instinct, especially in a young horse or an older horse with a handler he does not trust. It is perfectly natural for a horse to pull his foot away if you try and pick it up, he must be taught to overcome his instinctive fear and handling of a foal's feet at an early age saves much hassle later on. Notice how uneasy horses are if there is a dog running around during shoeing, when they must stand on 3 legs for long periods. Dogs are predators, and a horse's natural enemies in the wild, therefore even if a horse is used to dogs, when he is in a defenceless state his instinct is to be afraid. In fairness to both your horse and your blacksmith, it is better to keep the dog shut in during his visit.
Reluctance to leave the stable yard or a group of horses goes back to the instinct of safety in numbers. A horse needs to keep his head down for long periods to eat enough to maintain himself in the wild state, when his head is down he cannot see predators. This is where safety in numbers comes in, as herds always have some 'watchers' while others are grazing, to raise the alarm should a predator be sighted. Therefore alone the horse feels very vulnerable and instinct tells him to stay with the herd for safety.
No predators on his back, is a natural deep-rooted instinct ensuring survival. This is often in direct opposition of what we wish to do with a horse, and the amount of contact a horse has had with humans during his life has a direct influence on how strong this instinct is. For instance a horse that has lived virtually wild until it's training begins is far more difficult to train to saddle than one who has lived close to man all it's life. From personal experience of training young horses from many different backgrounds I have never found an exception to this. In saying 'difficult' I mean this relatively.
Horses that have been well handled from an early age do not seem to fear a person on their backs and accept it immediately with little or no resistance. Horses that have not been handled very much have an in-built fear of man, as a predator, and are more likely to resist, i.e. by jumping away when someone first attempts to mount them or by bucking when the weight of a person is felt on their backs. In except a very few cases this fear is overcome with patience and reassurance, but one needs to move quietly and tactfully with this type of horse or they become easily upset. In the case of breaking a horse to harness, much more ground work is done than before backing, in most cases, but even so a horse that has not been handled is much more likely to take fright at long reins unless very carefully introduced. This does not in any way mean that the horse is 'bad', it simply is unused to man and his demands, many of which, to a horse, are very dangerous.
Lack of understanding of how a horse thinks can lead to many unnecessary conflicts, horses think like horses not like humans, and to endow your horse with human characteristics can be very dangerous.
In moments of stress or excitement the horses will always act from instinct and can injure us easily without any intention of doing so. For instance, I remember feeling particularly stupid getting up out of the mud after standing, foolishly, in front of an Akal Teke stallion, right in his blind zone. He saw another horse, leapt forwards and literally flattened me with out realising I was there. I must say he did notice when he hit me, but it was too late then! Luckily I wasn't hurt and my main concern was that no-one else had noticed my stupidity!
Although it is very necessary to build a bond with every animal you work with, this should be based on respect for one another. If you encourage your horse to think you are another horse, don't be surprised when he takes a playful lump out of you, just as he would one of his contemporaries in the herd. He needs to respect that you are different from him and that you are the 'leader'. Horses in a domestic situation look constantly for guidance and this is your chance to build a good relationship with your horse. This delicate balance of trust and respect is achieved by consistency in your dealings with the horse at every level, firmness when he does wrong and praise when he does right. Horses are very responsive to voice and quickly learn 'good boy' and 'no'.
I cannot over-stress this point as an undisciplined horse is a potentially dangerous one.
THE HORSES SENSES A ITS VIEW OF LIFE
by Sue Tanzer
With eyes on the side of his head, the horse can see almost all-round himself, although he has a blind zone behind him and a little way in front of his head. The blind zone means that if you walk straight towards a horse you disappear when you are right in-front of him, to keep you in his vision he will either turn his head away or walk backwards, both actions are likely to be interpreted as 'not wanting to be caught'. Approaching from an angle keeps you in the horse's view all the time, although when you are a short distance away he may swing his head around towards you to get a binocular vision. Hence the old adage, 'approach a horse towards his shoulder'. Many old wisdom's from generations back hold very true and although our forefathers did not have the scientific knowledge available today they learned a lot by practical experience of what did and did not work when handling horses.
Not surprising, horses dislike activity in the blind zone where they cannot see it and unless they are very relaxed they will invariably turn their heads and sometimes their whole bodies to try and see what's happening. Any movement in this blind zone may be interpreted as threatening, especially by a young or little handled horse and if the horse is unable to move away or turn his head he is quite liable to kick out. Again, the old adage ' never approach a horse from behind, he might kick' holds true.
Focusing: Horse do not seem able to change their lens shape to focus as can many animals, and 50 years ago it was thought that they focused on distant or near objects by raising or lowering their heads due to the retina being 'ramped i.e. sloping, so that the bottom of it was nearer the lens than the top. Now this is known to be untrue and what has been discovered is that in the upper and lower extremes of their eyes horses are long-sighted, and the centre of the eye focuses on near objects. The retina vision is more detailed as there is a higher concentration of visual cells there. Also the cinema-scope of the horse's eye is not round, like ours, but much wider and shallower, extending almost all the way round the body.
To focus on objects close beside them, horses must either keep their heads low, or if their heads are high, tilt them sideways. If this tilting is prevented in a ridden, or driven, horse, they will have to skip sideways to get further away and reduce the degree of tilting needed. This action (spooking or shying) is often punished either deliberately or by loss of balance and snatching at the reins. The horse then learns that such objects hurt and try to avoid them more quickly, thus compounding the problem. Hence you see that the horses' view of life on a physical level is not the same as ours, and if we try to understand more about what the horse sees and how he needs to adjust his movements to see objects clearly, it may help us to understand him and communicate better with him.
A horse's ears are far more sensitive than ours, and far more selective, suggesting that their range of both high and low notes is greater than our own. For instance, a horse will hear the noise of another horse approaching long before we, sitting on their backs or riding just behind them, do. Horses ears are funnel shaped and very mobile, with 16 different muscles to move them, enabling the horse to catch sounds from any direction. Different ear positions show various things in 'Equus', the name given to the horse's language by Monty Roberts.
Ears pricked show extreme attention forwards
Ears to the side show listening to that side, when 1 ear,
Both ears drooping show relaxation and drowsiness
Ears half back, submission, doziness
Ears back, attention backwards, submission
Ears flat back, anger or fear, often the ears are not parallel, showing split attention
By reading a horse's mood and intentions accurately, many unnecessary conflicts can be avoided.
by Sue Tanzer
Calls - several different
Neigh, contact or recognition. Horses recognise others by their neigh just as we do by voices.
Stallion's neigh, recognisable by grunt at end.
Hollywood film maker constantly use a neigh in wrong situation, i.e. as fear instead of recognition.
Nickers, divided into greeting, i.e. to human friend, especially with food. Stallion's courtship nicker, low and forceful. Maternal nicker of a mare to her foal.
Squeals, very close contact, especially sexual. Often goes with stamp of forefoot, showing warning, or strike out of forefoot, a stronger threat.
Snorts, alarm and challenge signals to alert rest of herd. Sign of excitement in domestic horses.
Conflict between fear and desire to investigate something strange.
Screams and roars, not often heard. Sign of horse in extreme emotional state, usually rage and fear during fighting. If ever a horse screams at you, get out of the way, he really means to hurt you. Very rare.
Grunts, effort, fighting or jumping. Pain, foaling or colic. Not a deliberate signal.
High blowing, noise made in FALSE NOSTRIL, usually sign of pleasure when cantering.
Nose blowing/Clearing, relaxed sound when horse feels well in his environment. Often made after working on long rein. Occasionally will reply if you do it back.
BODY LANGUAGE / POSTURE
Posture betrays emotional state. Horses watch each other constantly for signs of attitude.
Signs of body tension are alarm signals to a horse. Since horses include us in this posture watching, they interpret tension in us as an alarm signal. Tense, frightened people actually frighten horses and make then want to run away. Sight of stiff, jerky movements indicate danger to a horse. If we are leader then doubly worrying for horse.
People who get on well with horses always relaxed and unhurried, making horse relax. Many fierce horses, used to rough treatment are, surprisingly, very quiet with children, probably because they are relaxed.
Emphasis on OUTLINE as potent signal explains why the sight of a familiar person wearing an unfamiliar hat or carrying something large can be source of fear for horse. They look for outlines, not features and the change worries them.
TAILS and EARS
Good forms of signalling as very visual.
High-tailing, shows excitement . Can also be used by mares to attract stallion but then combined with lower head carriage and drooping ears so as not to be mistaken for a 'startle' position
Tail flattening submission and fear
Tail lashing, annoyance and irritation, often seen in frustration and conflict
Ears best indicators of horse's attention Turned in any direction show what horse is listening to.
Turned back not necessarily bad temper, can be listening backwards.
MOUTHS and NOSES
Ears and tails signal form as alter outline. Mouth movements are also high contrast signals, showing submission, tension or threat to bite.
'Mouthing' by young foals is a submission signal. Droop ears, long neck and snapping movements of mouth. Very young foals mouth at anything big that moves, later they become more discerning and only do it when approaching older horses. Note during 'join up' horses mouth, showing submission.
Tight mouth shows tension, fear, mild anger.
Saggy mouth shows, relaxation but can also show exhaustion and pain when combined with flared nostrils, showing they are sunk deep inside themselves.
Long nose, wiggling, shows intention to scratch, roll or search in pockets. Mutual grooming approaches begin this way.
Nose wrinkling is sign of annoyance, pain. Sometimes used with ears back as a mild threat.
Head thrust, nose tipped abruptly forwards and upwards with jerk of neck. Aggressive threat movement. Commonest threat between horses. May become a lunge, where whole body is used, or extreme cases, a charge.
Nudge, attention seeking, can be to show distress to handler.
Loafing horses nudge companions to move them or start mutual grooming.
Head shakes, natural way of dislodging annoyances such as flies and dust after rolling. Also used in frustrating conditions, such as wishing to bite but not daring or unable to reach food. Annoyance at the bit, bridle or at being ridden at all. Shaking and tossing usually combined.
Nose shake, poll stays still and nose only moves. Often used by stallions displaying, either to another stallion or to mares. Often also seen by ridden horse after completing difficult task.
Jerk back, sharp backwards and upwards movement. Usually away from something frightening, horse or person. Carried further it becomes a rear, especially in youngster. Half asleep horses also jerk heads upwards as nodding off, usually to dislodge flies, has annoyance connotations.
Head bob, with pricked ears and intent stare. Trying to focus on middle distant object puzzling him.
Taken From Equine Behaviour