Proboscidea, Hyracoidea, and Sirenia

Question 1

Characteristics of all 3 Orders

Answer 1

• Non-ruminanting herbivores
• No clavicle
• Short or no nails
• Abdominal testes and no baculum
• Hindgut fermenators
• Horizontal tooth replacement (except hyraxes)
• Females have pectoral teats

Question 2

Order: Proboscidea

Answer 2

• Elephants

- 2 to 3 species, (African, Asian, and maybe Indian)

Question 3

African Elephant Morphological Traits

Answer 3

• Larger size
• 3 nails
• 20 pairs of ribs
• different occlusal surface on cheekteeth compared to Asian
• 2 lips on trunk

Question 4

Asian Elephant Morphological Traits

Answer 4

• 4 nails
• Smaller size
• Larger head and is above shoulders
• Single lip trunk

Question 5

Elephants

Answer 5

• Large family herds
• Destructive to forests and agriculture
• Sexual maturity at 9-12 years, peak is 25-45 years
• Reproduction tied to wet season

Question 6

Reproduction in Elephants

Answer 6

• Estrus 2-4 days in later part of wet season/first part of dry season
• Gestation 22 months
• Males reproductive for 2-3 moth period called musth
• Males breed from 25-50 years old

Question 7

Elephants and Sexual Selection

Answer 7

• Males have large testes w/ lots of sperm, compared to large ova in females
• Difference in size of gametes in mammals is called Anisogamy
• Bateman gradient pertains to elephants & other mammals where male-male interaction is intense for females

Question 8

Female Parental Investment

Answer 8

• Prefer bigger, stronger, older males
• Herd usually unrelated made up of tightly knit females
• Allomothers help in all aspects of raising calf with the mother

Question 9

Male Elephant Strategy

Answer 9

• Little investment in offspring, but does protect herd
• Waits long time before sexually mature, must go thru teen years
• Seeks bonds w/ other males to prevent aggressive actions
• Can kill any land animal, are also known to destroy villages and kill ppl as teens

Question 10

Mating Systems

Answer 10

• Monogamy
• Polygyny: 1 male mates w/ many females
• Polandry: Female mates w/ multiple males (rare in mammals, African Wild Dog)
• Promiscuity: both sexes have multiple matings after prolonged associations
• Things like food supply, population and predation determines mating system sometimes

Question 11

Rock Hyrax (Procavia capensis)

Answer 11

• Found across Africa
• Live in rock crevices
• Large groups of 10-80 animals

Question 12

Hyraxes

Answer 12

• Have padded feet w/ nail reduction
• Specialized grooming claw or analogous structure present
• Use rocks as outposts and give alarm calls when disturbed
• Mating systme is polgyny

Question 13

Order: Sirenia

Answer 13

• Manatees and dugongs

- Inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters

Question 14

Dugongs

Answer 14

• Fluked tails
• Have no nails
• Teeth don’t continuously grow via HTR
• Incisors/tusks grow posteriorly till puberty, then erupt
• Smaller in size rarely exceeding 3 meters
• Pachysotosis: condition where ribs and other bones are more solid and lack marrow
• Densest bones over any animals, and helps as ballast to suspend below waters surface

Question 15

Dugongs and Reproduction

Answer 15

• Gestation 13 months
• Births one calf at a time, and nurses for 2 years
• Sexual maturity b/t 8-18 years
• Despite longevity, females only birth only few times in their life

Question 16

Manatees

Answer 16

• Have nails. except for Amazonian
• HTR
• Emit wide range of sounds and other senses in communication
• Capable of understanding discrimination tasks, complex associated learning, and long term memory

Question 17

Manatees and Reproduction

Answer 17

• Generally solitary and monogamous
• Gestation is 12 months
• Breed twice a biennial
• Takes 12-18 months to wean calf

Question 18

Fossil Record

Answer 18

Arose from primitive group called Condylarthra 65mya