Mammalogy
(Spring 2015 Althoff - reference FDVM Chapters 6 & 20)
LEC
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Claws, Nails, Hooves, Horns, and Antlers
Claws, Hooves, & Nails
• ______________ tissue
• Derived from “stratum germanitivum”
layer of the _____________
(see Fig. 6.2, p98 - “stratum basale”)
• In STRATUM BASALE, cells continuously
divide and are pushed ____ by cells
produced below them. Lack of
________________ from reduction of
capillaries results in less metabolic
activity
1
DERMIS
FDVMK p98, Fig. 6.2
Keratin
• _________ produced by the epidermal
cells
• a “coiled” protein
• ___________
• when mature, it is ________ tissue
2
Claws
POLAR BEAR
•
•
•
•
SIBERIAN TIGER
Most “_________” of keratinized structures
Occurs at the ______ of the digits
Grows _____________
Consist of 2 parts:
a)
b)
• UNGUIS--dorsal,
scale-like plate;
surrounds
subunguis
• SUBUNGUIS-ventral
3
Nails
• Specialized “claws”
• Found only among in ___________
• Facilitate better grip, more precise object
manipulation by hands & feet
• Only cover _________ surface
• Co-evolved: __________________
_________________ in the dermis at the
ends of digits of primates
Hooves
• Specialized “___________”
• Found only among perissodactyls and
artiodactyls
• Unguis _______________ surrounds the
subunguis
• Adaptation combined with ___________ in
number of digits
• Constantly wears away slowly at ________
surface
4
Basics....Generalities
• Antlers are _________ annually
• Horns are ___________ annually
• Ungulates only ones with
horns or antlers
• Perissodactyls _________ have
• Artiodactyls _______ have
Perissodactyls
• Examples: Horses, tapirs,
rhinoceros
• Exception: rhino “horn” is or
________ origin
and lacks a
bony core
5
Rhino -- an exception
(RHINOCEROTIDAE)
• ____ bony core
• ____ keratinized
sheath
• Keratinized
fibers
• ____ attached to
bone
“fused hairs”
DERMIS
FDVMK p98, Fig. 6.2
6
DERMAL PAPILLA--composed of blood and
nerves which service follicle
Artiodactyls
• Two major groupings between
ungulates showing major
differences in “horns” vs.
“antlers”
Giraffidae
vs.
Cervidae
vs.
Bovidae/Antilocapridae
7
Giraffe
(GIRAFFIDAE)
• Bony core (ossicone)
• Hair-covered
epidermis (skin)
• Fused to cranium
Giraffe OSSICONES
8
Deer, Elk, Moose
(CERVIDAE)
Cervids - ANTLERS
• Made of _______
• Usually ____________
• Supported on “___________” -- raised
extension of _________ bone
• ___________ …exceptions:
a) caribou (reindeer)--both sexes
b) Chinese water deer--none
• Velvet--________, highly ____________
skin.
9
Cervids - ANTLERS…con’t
• Aside from __________ tissue, fastest
growing tissue known
• Antler size and number of tines function
of: a)
b)
c)
• Shed ___________
• ____________ antlers:
caribou, moose,
fallow deer
Pronghorn
(ANTILOCAPRIDAE)
The “__________”
when it comes to
horns & antlers
10
Pronghorn
(ANTILOCAPRIDAE)
Pronghorns - “Unique” Horns
• _______ core covered by ___________
sheath
• “Horn” sheath shed annually, new one
grows ______________
• Males have, most females have but they
are smaller
• Upright horns with ______________ and
short, anterior branch (prong)
• ______ N. American ungulate with this type
of horn
11
Bison, Gazelle, Oryx, Water Buffalo
(Bovidae)
Grant’s gazelle
fringe-eared oryx
springbok
Sichuan takin
12
Marco Polo Sheep
…subspecies of ________
which is 1 of 2 thought to
be the ancestor/origin of
domestic sheep (the other
is early mouflon)
Kyrgyzstan
CHINA
Tajikistan
Afghanistan
Pakistan
Bovids - Typical Horns
•
•
•
•
Bony core with _________________
“Horn” sheath over this bony core
“Horn” sheath __________________ shed
Males have, females of some species
have
• __________________
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Bovids: HORNS...con’t
• Horns are never branched
• Horns are typically long &
gracefully curved
• Bighorn sheep, Mt. Goats,
Bison, cattle in
N. America….many,
many species in Africa
& Eurasia (Fig. 20.24, p400)
Functions of Horns & Antlers
• _______________: Show dominance
among males and fight for mates,
territory during “rut.” Therefore,
selection “for” larger, more massive
head “ornaments”
• ______________: challenge
conspecifics, ward off predators
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