Mammals
Mammals
Mammalian Characteristics
Mammalian Diversity
Bumblebee bat
Class Mammalia

Order Carnivora
– Suborder Pinnipedia
 Family Otariidae
 Family Phocidae

Order Cetacea
– Whales, dolphins and porpoises
Pinnipeds

Characteristics:
– Must come to land/ice to breed
 Pagophilic
– Feed on fish and squid
– Most large in size
– Residents of cold water
– Enhanced diving ability
Family Otariidae

‘Eared Seals’
Family Otariidae

Steller Sea Lion
– Eumetopias jubatus
Family Phocidae

‘True Seals’
Order Cetacea

Suborder Odontoceti
– Family Physeteridae (sperm whales)
– Family Delphinidae (dolphins)
– Family Phocoenidae (porpoises)

Suborder Mysticeti
– Family Balaenidae (right whales)
– Family Balaenopteridae (rorquals)
Odontoceti

Toothed Whales
– Single blowhole
– Sexual dimorphism
– Echolocation
Family Physeteridae

Sperm whale (Physeter macrocephalus)
• Squared head
• 36-50 conical teeth in
lower jaw
• Low dorsal hump
• Off-center blowhole
Spermaceti Organ
Essex
Family Delphinidae

Killer Whale (Orcinus orca)
• Distinct coloration
• Prominent dorsal fin
• 20-26 teeth in upper
and lower jaws
• Fast swimmers
Family Delphinidae

Atl. Bottlenosed Dolphin (Tursiops truncatus)
• Well-defined beak
• Lack patterns
• Blue-gray to brown
• Coastal and offshore
forms
Echolocation

1500 m/sec

Object is 3
sec away

4500 m away
Mysticetes

Baleen whales
– Divided blowhole
– Differences in size between sexes
– No echolocation
Family Balaenidae

Northern Right Whale (Balaena glacialis)
• Narrow, arching
rostrum
• No dorsal fin
• V-shaped blow
• No throat grooves
Family Balaenopteridae

Humpback Whale (Megaptera novaeangliae)
• Flat, broad head
• Long flippers
• Small dorsal fin with
hump
• Ventral throat
grooves
Mysticeti Feeding Types
Swimming

Streamlined bodies
Breathing

Quick breaths
– Can empty and re-fill lungs in 2 seconds!!!

Renew ~90% of air in single breath
– Humans ~10%
Diving Physiology

More blood than non-diving mammals
– More hemoglobin
– More myoglobin
Dive Reflex

Heart rate slows
– Bradycardia

Blood flow reduced
– Vasoconstriction

Increase in
lactic acid
The Bends

Decompression Sickness
– N2