Sheep Skull

The museum houses a variety of different mammalian skulls which are great teaching aids for topics such as eco-morphology, by comparing the different shapes and sizes of homologous structures between species of differing ecology.

Below is the skull of a sheep (Ovis aries), a herbivorous animal that selectively feeds on the tender, new growth of grasses and herbaceous plants. This discerning feeding behaviour is paralleled by the morphology of the teeth in that incisors are only present on the lower jaw where they are opposed, on the upper jaw, by a hard palate. Together these two surfaces act as knives on a chopping board to cut through fine foliage. The sheep’s molars are ridged to increase the efficacy of the grinding motion which is brought about by the lateral movements of the jaw. Being herbivorous means being able to focus on one individual (ie a prey item) is not crucial but remaining vigilant for potential predators remains important, as such, the position of the eye sockets in sheep (and most herbivores) is very lateral allowing (in conjunction with pupil shape) a view of up to 320 degrees.

This example of a herbivore’s skull can be compared to those of carnivores and omnivores.

 

Peccary skull

The museum houses a variety of different mammalian skulls which are great teaching aids for topics such as eco-morphology, by comparing the different shapes and sizes of homologous structures between species of differing ecology.

Below is the skull of a Peccary or Javelina (Tayassu tajacu) an omnivorous animal, meaning it eats both plant and animal material. Their variety of diet means that omnivores, such as the peccary, have a range of medial features between carnivores and herbivore. As can be seen on the peccary skull the teeth at the front of the jaw have the sharp chopping incisors and the stabbing canines while the teeth grouped together at the back of the jaw have both cutting premolars and grinding molars. The position of the eye sockets is also medial as they do not have the range of a herbivore but are not as forward facing as a carnivore.

Tiger Skull

The museum houses a variety of different mammalian skulls which are great teaching aids for topics such as eco-morphology, by comparing the different shapes and sizes of homologous structures between species of differing ecology.

Below is the skull of a tiger (Panthera tigris), a voracious carnivore with large, penetrating and grasping teeth as well as thin slicing teeth. The use and efficacy of these predatory weapons are facilitated by large jaw muscles which require large attachment areas on the skull and extra space to pass beneath the cheek bones. The position of the eye sockets is also typical of a predator, with their forward facing position they allow good depth perception and the ability to focus on individual prey.

This morphology can be compared to that of a herbivore or omnivore skull.

Humans

The human skeletons held here at the McGregor Museum are said to come from India (prior to the 1985 ban on the export of human remains) although even past curators are unsure of their origin. The subject of the origin of such remains was largely avoided when purchasing and it is believed that many of the models are the result of grave robbing. The shut down of this trade in 1985 has led to a black market in human bones out of India with large reputable institutions still conducting trade in this illegal market according to some investigative journalists. Until there is a pathway set up for voluntarily donating skeletons to science these real human skeletons are an invaluable resource to teaching institutions and digitising such assets ensures their use and maintenance for years to come.

Quadruped Hind Leg Anatomy

The below series of photographs use McGregor Museum specimens to illustrate the ancestral similarities (synapomorphies) and derived differences (apomorphies) between the hind leg of different quadrupedal mammals.  Keep in mind the habit and locomotory behaviour of these animals as you compare their limb structure.


Here the leg of a goat (Capra aegagrus) represents the unguligrade anatomy of locomotion.


Likewise, the hind leg of the leopard (Panthera pardus; left) and european hare (Lepus europaeus; right) illustrate the digitigrade’s anatomy.


The above black bear (Ursus americanus) hind limb is representative of plantigrades anatomy.