Top Five (Extant) Mammals of All Time

Greetings blog readers, long time no write. Writing from the dad perspective I would like to get on board the list trolley. Since we visited the zoo today, I felt inspired to list my top five mammals of all time. Really, all time is a bit of an overstatement since I am not including fossil critters. I have debated internally long and hard on this one, and decided this list will be extant mammals and another list will be for extinct mammals. Remember, these are my personal choices and you are always free to disagree. Here we go:

5) Small-Clawed Otter (Aonyx cinerea)


This aquatic mammal swims the swamps and wetlands of Asia and is exceptional for its hands. The claws on the forepaws do not extend beyond the fleshy part of the digit thus giving them a very primate-like hand that is good at grasping and manipulation.

4) Kangaroo Rat (Dipodomys deserti)


This little rodent inhabits the desert Southwest of North America and is on this list because of its amazing kidneys. They are four times more efficient at retaining water and excreting salts than a human's. This means they could literally drink seawater all day long and never get dehydrated. However, since seawater is never on the menu they just never drink water for their whole lives! For those biochemists reading the blog their trick is to conserve water produced during the oxidative phosphorylation (metabolism) of carbohydrates.

3) Fossa (Cryptoprocta ferox)


This largest mammalian carnivore on the island nation of Madagascar is actually most closely related to the mongoose. Through convergent evolutionary processes, this weasel-like mammal looks very much like a large predatory cat. This critter makes the list because it is such a great example of how geographic isolation leads to organisms filling unlikely nichespace within an ecosystem. The adaptive significance of a cat-like body plan in this mongoose-like mammal is evident when it is observed catching a leaping lemur in midair.

2) Colugo, or flying lemur (Cynocephalus variegatus)


This cool mammal is found in the Indomalayan region of the world and it is really the only living representative of an entire order of mammals that is thought to be closely related to our order Primates. This means that the earliest primates may have shared a similar adaptive profile with these gliding lemur-like mammals found in Southeast Asian forest refugia.

1) Dolphin (family Delphinidae)


Rather than choose one species, I include all dolphins in the family Delphinidae. This is because they all share the incredibly well-engineered body plan that we recognize when we see these fully aquatic mammals. For starters, they live in highly sophisticated social groupings and have demonstrated individual self-conciousness. They are capable of communicating, navigating, hunting, and otherwise detecting their surroundings through echolocation. Their outward appearance is like a torpedo (fusiform) and so they are capable of incredible feats of strength and acrobatics within a highly viscous aqueous medium.

Dolphins make this list because they provide a great comparative mammalian model for understanding the evolution of higher primate intelligence. If we can understand the social and ecological significance of dolphin intelligence, we may begin to shed light on why apes and humans also evolved into highly cerebral animals.