Marsupialia and Insectivores

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Marsupialia and Insectivores

• Opossum, Hedgehogs, Moles and Shrews

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Objectives of Lab

• Learn to identify local mammals, as well as other
  North American species (dental formulas, skin,
  skull, and post-cranial morphology)
• Associate natural history (food habits, habitat,
  and reproduction) with each species
• Common collecting techniques

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Didelphis virginiana

• Only marsupial (Infraorder Metatheria) in Texas -
  Opossum
• Dental Formula 5/4 1/1 3/3 4/4 50
• Habitat Virtually everywhere, particularly
  around people.
• Food Fruits, berries, mast, insects,
  earthworms, garbage, carrion, bird eggs.
• Reproduction Gestation 12-13 days. Newborns
  climb from vagina to pouch and attach to a teat.
  1-2 litters per year.
• Playing possum is actually a seizure and a
  common defense mechanisms.
• Capture techniques Box traps baited with
  catfood, roadkills, handcapture.

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Tlacuatzin canescens

• Gray mouse opossum
• Dental formula Dont have skull
• Habitat Found in Mexico in forested habitats of
  Sonora, Oaxaca, Yucatan, and Tres Marias Islands.
• Food Eats mainly insects.
• Reproduction Active year round. See other
  opossums.
• Trivia This little guy may be in Baja
  California, as a mandible was recovered from an
  owl pellet there in 1977.

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Family Erinaceidae

• Hedgehogs
• Oldworld Group
• Now a common pet in US
• Diet Inverts, small vertebrates, carrion.
• Many defensive spines (5000 per critter)

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Family Talpidae

• Moles and Shrewmoles
• Common throughout Holoarctic
• Specialized for Fossorial Life
• Look for these specializations as you examine the
  species we have provided.
• Capture techniques Harpoon traps, pitfall, hoop
  traps, and scavenging

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Scalopus aquaticus

• Eastern Mole
• Dental Formula 3/2 1/0 3/3 3/3
• Habitat Found from Mass. to Nebraska S to Texas
  in well drained, loose soil, in woods or open
  areas. Often in yards and gardens. In Texas,
  found in the eastern 2/3 of the state.
• Food Earthworms, snails, slugs, and insects.
• Reproduction one litter per year in April or May
  with 2-5 young. Animals can be sexes by number
  of openings, but difficult on live specimens.
• Sign Produce numerous tunnels and molehills of
  pushed out dirt.

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Condylura cristata

• Star-nosed mole
• Dental formula 3/3 1/1 4/4 3/3
• Habitat Found in the northeastern United States
  and along major water sources (oceans and great
  lakes). Normally in wet or murky areas of woods
  or open places.
• Food Earthworms, snails, slugs, and other
  aquatic invertebrates.
• Reproduction One litter per year in April or
  May, with 3-7 young.
• Trivia Most aquatic of the moles, can even swim
  underwater and is sometimes taken in minnow
  traps. Nose tentacles may be sensory, or as
  electrical sensing devices for prey detection.

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Neurotrichus gibbsii

• Shrew-mole
• Dental formula 2/1 1/1 3/4 3/3
• Habitat Pacific coast from BC to California.
  Found in riparian habitats, as well as wet
  forests and prairie lands
• Food invertebrates such as termite, sowbugs,
  pillbugs and earthworms.
• Reproduction Typically one one litter per year
  with 1 to 5 young in that litter.
• Trivia These are moles that dont create burrow
  systems. Instead, they make shallow burrows in
  loose topsoil and rummage through the leaf
  litter, like shrews.

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Family Sorcidae

• Shrews
• Common on all continents except Antarctica and
  Australia
• Two subfamilies Soricinae (red-toothed shrews)
  and Crocidurinae (white-toothed shrews)
• Ground dwelling creatures that largely resemble
  some of the most primitive mammals.
• Largely feed on invertebrates of all kinds, but
  will attempt to kill most animals its size or
  smaller.
• Capture Techniques Pitfalls, empty bottles or
  cans, snap-traps and shermans (for Blarina)

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Sorex cinereus

• Masked shrew
• Dental 1/1 5/2 3/3
• Habitat found in a variety of habitats from salt
  marshes, meadows, woods, and mountains. Its
  range is most of the northeastern United States.
  Locally found in moist fields and bottomlands.
• Food Insect material, earthworms, mollusks.
• Reproduction Nest of leaves or grass beneath a
  log or stump. Three litters per year of 4-10
  young.
• Trivia Like most shrews, these animals have
  limited echolocation for hunting, and do not
  hibernate in winter.

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Sorex (Microsorex) hoyi

• Pygmy shrew
• Dental formula 1/1 5/2 3/3
• Habitat Found in northeastern United States
  around the Great Lakes and in Appalachia in
  mature forests.
• Food Insect larvae, spiders, and beetles
• Reproduction May only bred once a year, but has
  5-8 young per litter.
• Trivia This shrew rivals the bumblebee bat for
  the worlds smallest mammal, weighting around 2.0
  grams

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Notiosorex crawfordi

• Crawfords Gray shrew or Desert shrew
• Dental formula 1/1 4/2 3/3
• Habitat SW and SC USA to Baja California and N
  and C Mexico.
• Food Insect larvae and adults, as well as dead
  mammals, birds, and lizards.
• Reproduction May only bred once a year, but has
  3-5 young per litter.
• Trivia Unlike most shrews, these dont use
  underground burrows, and consume 75 of their
  weight a day, without drinking water.

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Blarina brevicauda and Kin

• Short-tailed shrews
• Dental formula 1/1 6/2 3/3
• Habitat Found throughout the northeastern United
  States in a wide variety of habitats, from salt
  marshes to stunted mountain timber. Generally in
  the vicinity of water
• Food General invertebrates and other oddities,
  like plant material and Endogone
• Reproduction 3 or 4 litters per year of 4-6
  young each.
• Kin B. carolinensis is found on the Gulf coastal
  plain, while B. hylophaga is found on the
  southern plains. Both these sister taxa have
  been found in Texas.

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Cryptotis parva

• Least shrew
• Dental formula 1/1 4/1 3/3
• Habitat Found in marshy areas of the eastern
  United States south to Panama. Locally, they
  tend to be taken in grassy, weedy, and brushy
  fields.
• Food Eat a variety of small insects, mollusks,
  and earthworms
• Reproduction Several litters, with 2 to 7 young
  each, are produced from March thru November in
  the northern end of its range. They may bred
  year round in the south.
• Trivia Sometimes called the bee shrew, for its
  habit of living in bee hives and eating adults
  and larvae.