Ungulates Flashcards
‘Ungulates’ are comprised of what taxonomic groups?
Artiodactyla (even-toed ungulates)
o Pigs, hippos, camels, ruminants)
Perissodactyla (odd-toed ungulates)
o Rhinoceros’, hippos, tapirs
Key characteristics of the order Artiodactyla feet and toes
o 1st digit lost (only 4 toes)
o Cloven-hoof (2 weight-bearing toes)
o Toes 3 & 4 well-developed, 2 and 5 reduced or absent
o Plane of symmetry passes between toes 3&4
Key characteristics of the order Artiodactyla teeth
o Upper incisors always reduced or absent
o Canines small or incisorform
o Cheek teeth tend to be selenodont
Key characteristics of the order Artiodactyla Stomach
o 4-chambered??
What are ‘Cetartiodactylas’?
- The combination of artiodactyla and cetaceans into one order because of fossil-evidence
What are the two suborders of Artiodactyla?
Suiformes (non-ruminants)
o Pigs, hippos, peccaries
Ruminantia
o Ruminants – 4 chambered stomachs
What are the three families that comprise the ruminants?
Cervidae
o Moose, elk, mule-deer, white-tailed deer, caribou
Bovidae
o Bison, mountain goats, bighorn sheep, thinhorn sheep, cows
Antilocapridae o Pronghorn (not in bc – ab/sk)
How do Perissodactylas vary from Artiodactylas with respect to feet & toes?
- 3rd digit is most prominent (plane of symmetry passes through this digit)
- First digit is lost in all species
- Horses have single functional toe on each foot, rhinos have 3
- Unguligrade: heel and sole of foot never touches ground
How do Perissodactylas vary from Artiodactylas with respect to teeth
- Lower canines usually present
- Lophodont
How do Perissodactylas vary from Artiodactylas with respect to stomach
- Mono-gasteric stomach (no chambers)
- Enlarged cecum (hind-gut fermenters)
Define selenodont
Lophs run side to side to create more surface area
Define lophodont
Have lophs that run between cusps (elongated ridges)
Define brachyodont
Low-crowned teeth (humans)
Define hypsodont
high-crowned teeth, lots of extra material for wear (cows and grazers)
Define bunodont
cheek teeth with low-rounded cusps
Define aquatic
Animals swim (otters)
Define volant
Animals glide
Define Cursorial
Animals that run rapidly for long distances
Define scansorial
Animals are climbers (mountain goats and woodpeckers)
Define arboreal
Animals spend most of their time in trees (squirrels)
Define saltatorial
Animals are hoppers (Deer mice)
Define fossorial
Animals are diggers, live in burrows (pocket gophers, badgers)
What two factors determine speed an animal can travel?
- Length of stride
- Rate of stride
Describe the 4 main adaptations to lengthen stride – be as thorough as possible
Length of stride: based on three basic patterns of cursorial movement (above)
Lengthen limb elements
o Elongation of metapodials (metatarsals + metacarpals)
Include the scapula as part of the limb
o Allows scapula to absorb shock as opposed to rest of body
o Clavicle is reduced or lost in animals that do this
Flexing the spine
o Bounding or galloping
Describe the 2 main adaptations for increasing frequency of steps – be as thorough as possible
# of joints o Each new joint yields increase in foot speed
Muscles acting on bones behave as force and lever systems
o Muscles close to joints move joint through wide angle and make bones move faster
What are the 4 main chambers of a ruminant’s stomach and what are the purpose of each chamber?
Rumen
o Fermentation chamber
o Anaerobic environment, constant temp and pH
o No bacterial juices but does have bacteria and protozoa which can break down cell walls
o About 70% of cellulose is absorbed directly into the bloodstream from the rumen
Reticulum
o Compacts food into cuds for further breaking down by teeth
Omasum
o More breakdown by bacteria and micro-organisms
Abomasum
o The true stomach
o Has glands that secrete hydrochloric acid, pepsin, lipase
o Secretes lysosome – breaks down bacterial cell-walls
o Plant protein is transformed into animal protein
When and where does rumination occur and why are these an advantage?
- Rumination typically occurs when the animal is resting and not eating, which is a considerable fraction of the animals lifespan
How does digestion vary between artiodactylas and perissodactylas?
- Perissodactyls are hind-gut fermenters With only 1 chamber
- Microbial symbionts in caecum help break down cellulose
- Purpose of caecum is to ferment complex carbohydrates of the herbivorous animals into fatty acids and to absorb these for use in the body
How do antlers and horns vary from each other, with respect to:
Taxonomic group and genders containing them
Antlers:
o Found in Cervidae
o Only in males
Horns:
o Occur in all male species of Bovidae (often females)
o Present in both sexes often for large species but only male for small
How do antlers and horns vary from each other, with respect to
Structure
Antlers:
o Bony, branched structures
o Shed annually
Horns:
o Bony core with a sheath of Keratin
o Horns are never branched
How do antlers and horns vary from each other, with respect to
How they grow
Antlers: o Grow from pedicels o Regulated by testicular and pituitary hormones o Start growing in April or May o Grow with skin and hair (velvet) o Velvet dies o Pituitary hormone stimulation decreases in winter (day-length) o Pedicel loses calcium and antlers shed
Horns:
o Horns never shed
o Start as ossicones (small lumps of cartilage)
o Fuse secondarily to skull bones
What triggers the antler growing process?
- Testicular and pituitary hormone
What family do antelope belong to and how does this family vary from other members of the artiodactyla?
- Antilocapridae
o Horns are branched
o Consist of a bony core and keratin sheath but sheaths are shed annually
