CAS 302: Caring for Companion and Working Animals - Lecture 1

CAS 302: Caring for Companion and Working Animals

Lecture Objectives

  • Key takeaways from this lecture include:

    • Classifying domestic dogs and cats according to their taxonomic hierarchy.

    • Discussing defining features characteristic of animals in the Order Carnivora.

    • Describing the common ancestry of cats and dogs, including their evolutionary divergence into separate groups.

    • Identifying key ancient species that led to the evolution of modern cats and dogs.

    • Understanding the movement of ancient species of cats and dogs to various parts of the world throughout the evolutionary process.

Taxonomy of Dogs and Cats

  • Domestic Dogs and Domestic Cats are classified as follows:

    • Kingdom: Animalia

    • Phylum: Chordata

    • Class: Mammalia

    • Order: Carnivora

    • Family:

    • Dogs: Canidae

    • Cats: Felidae

    • Genus:

    • Dogs: Canis

    • Cats: Felis

    • Species:

    • Domestic dogs: Canis familiaris (or Canis lupus familiaris)

    • Domestic cats: Felis catus (or Felis silvestris catus)

Order Carnivora

  • Order: Carnivora

  • Suborders:

    • Caniformia: Includes dog-like mammals.

    • Feliformia: Includes cat-like mammals.

Families within Carnivora

  • Family Canidae:

    • Contains 13 genera and 37 species, including:

    • Foxes, dogs, wolves, jackals

    • Notably, the genus Canis, which encompasses 9 species.

    • Example: Canis lupus familiaris (domestic dog).

  • Family Felidae:

    • Comprises 14 genera and approximately 45 species, including:

    • Cheetahs, lions, panthers, lynxes, pumas, leopards, tigers, jaguars, and other small and large cats.

    • Example: Felis silvestris catus (domestic cat).

Common Features of Carnivora Species

  • Defining Features of Carnivora include:

    • Primarily dietary carnivores, structurally adapted to a carnivorous diet.

    • Adaptations for running, indicating a terrestrial lifestyle.

    • Unique dental features adapted for a predatory diet, such as carnassial teeth.

Dentition of Carnivores

  • Structure of teeth:

    • Enlarged carnassial teeth are critical for carnivorous diets.

    • Chewing Motion:

    • Involves:

      • Upper jaw: Fourth premolar

      • Lower jaw: First molar

    • The chewing motion involves the inside surface of the upper fourth premolar sliding against the external surface of the lower first molar, allowing vertical jaw movement instead of lateral (side-to-side).

Ancient Origins of Cats and Dogs

  • Originating approximately 60 million years ago, the early ancestors known as miacids serve as the common ancestors for all carnivores.

  • Divergence occurred around 40-50 million years ago into two suborders:

    • Caniformia (dog-like lineages)

    • Feliformia (cat-like lineages)

Caniformia (Dog) Lineage

  • Key developments include:

    • Hesperocyon: Originated around 37 million years ago, marking the beginning of the Canidae family.

    • Early Caninae: Emerged approximately 34 million years ago.

    • Leptocyon: A notable genus present in the lineage from 37 to 15 million years ago.

    • Borophaginae: Early forms saw dispersion to Eurasia from 34 to 2 million years ago.

    • Notable divergences:

    • Fox Lineages: Present around 7-10 million years ago.

    • Early Canids: Evolved around 6 million years ago with species like Canis lepophagus.

    • Ancestors of the grey wolf appeared approximately 1 million years ago.

Feliformia (Cat) Lineage

  • Evolution and diversification:

    • Proailurus: Originated about 25 million years ago, marking the start of the Felidae family.

    • Pseudaelurus: Present from 10-20 million years ago, leading to the Pantherinae subfamily of large cats.

    • Machairodontinae: Known as saber-toothed cats, now extinct, emerged approximately 10 million years ago.

    • Early African Wildcat Ancestors: Evolved between 1-2 million years ago which eventually led to modern domestic cats.

    • Early Felinae: Originated around 10 million years ago, including divergence into genera such as lynxes, pumas, ocelots, and caracals.

    • Early felids appeared about 2-3 million years ago.

Next Steps: Domestication of Ancestors

  • Understanding the domestication process for cats and dogs:

    • Canis lupus familiaris: Domesticated from wolves around 20,000-30,000 years ago.

    • Felis silvestris lybica: Ancestor of domestic cats domesticated around 10,000 years ago.

    • Historical timelines suggest early interactions began between 300,000 and 500,000 years ago for canine ancestors and between 130,000 and 100,000 years ago for feline ancestors.