In a lineup, could you tell the difference, say, between a donkey and a mule? What about a turtle and a tortoise? A frog and a toad? Well, Irwin to the rescue! Today, we'll look at the often-time subtle differences between creatures that look the same but are actually different. Some differences are as subtle, though, once you know what to look for.
First up are the dolphin and the porpoise. Dolphins and porpoises are both cetaceans, the same family of mammals that also includes whales. There are 34 species of dolphins and only 6 different species of porpoises. Dolphins are characterized by their relatively long, narrow beaks studded with cone-shaped teeth, their curved or hooked dorsal (back) fins, and their relatively slender builds; they can also make whistling sounds with their blowholes, and are extremely social animals, swimming in extended pods and interacting easily with humans. Porpoises have smaller mouths filled with spade-shaped teeth, triangular dorsal fins, and bulkier bodies. As far as anyone has been able to tell, porpoises can't produce any blowhole sounds, and they are also much less social than dolphins, rarely swimming in groups of more than four or five and behaving very shyly around people.
Next up are turtles and tortoises. In the US, turtles are generally meant to include both real turtles as well as tortoises. In the Uk, however, turtles refer specifically to freshwater and saltwater Testudines (the animal order that embraces turtles, tortoises, and terrapins). And that's just two languages! Generally-speaking, tortoises refer to land-dwelling Testudines, while turtles is reserved for either ocean-dwelling or river-dwelling species. Most tortoises are vegetarians, while most (but not all turtles) turtles are omnivorous...eating both plants and other animals.
Hares and rabbits are another group that often gets confused. Hares "are comprised of about 30 species of the genus Lepidus; they tend to be slightly larger than rabbits, live on prairies and deserts rather than burrowing underground and can run faster and hop higher than their rabbit cousins (necessary adaptations for escaping from predators on open ground). Rabbits comprise about two-dozen species and are spread out over eight different genera. They prefer to live in shrubs and forests, where they can burrow in the ground for protection. Bonus fact: the North American jackrabbit is actually a hare! "You may wonder where "bunny" fits into all this nomenclature; this word once referred to juvenile rabbits, but now is applied indiscriminately to rabbits and hares alike, especially by children."
The next group is pretty confusing so you'll need to pay attention; possums and opossums. The North American mammals known as opossums are marsupials and account for 100 species and 19 genera! "The trouble is that American opossums are often referred to as "possums," which causes them to be confused with tree-dwelling marsupials of Australia and New Guinea of the suborder Phalangeriformes (and which, wouldn't you know it, are also called 'possums' by natives). Aside from their names, though, you're unlikely to confuse an Australian possum with an American opossum; for one thing, the former marsupials are distant descendants of Diprotodon, a two-ton wombat of the Pleistocene epoch!"
Okay, now we have donkeys and mules. The differences here come down to genetics. Donkeys are a subspecies of genus Equus (which also includes horses and zebras) that descend from the African wild ass and were domesticated in the near east about 5,000 years ago. Mules "by contrast, are the offspring of female horses and male donkeys (subspecies of Equus are capable of interbreeding), and they are completely sterile — a female mule can't be impregnated by a male horse, donkey or mule, and a male mule can't impregnate a female horse, donkey or mule. Appearance-wise, mules tend to be larger and more "horse-like" than donkeys, while donkeys have longer ears and are generally considered cuter. To complicate matters, there's also an equine called a "hinny." This is the offspring of a male horse and a female donkey; hinnies tend to be slightly smaller than mules, and are occasionally capable of breeding."
The next group we'll look at is, of course, frogs and toads. Both are members of the amphibian order Anura, which is Greek for "without a tail." All toads are frogs but not all frogs are toads. Frogs have long hind legs with webbed feet, smooth (or even slimy) skin, and prominent eyes, just like yours truly. Toads have stubbier bodies, dry and often warty (bumpy) skin, and comparatively shorter hind legs. As you may have already guessed, frogs are usually found near water, while toads can range for longer distances inland, since they don't constantly need to keep their skin moist. However, frogs and toads do share two important characteristics in common: as amphibians, they both need to lay their eggs in water (frogs in circular clusters, toads in straight lines), and their hatchlings pass through a tadpole stage before developing into full-grown adults.
And we'll end up with a look at seals and sea lions. The easiest way to determine the difference between these two aquatic-loving critters is by their size and cuteness. Both of these animals belong to the family of marine mammals known as pinnipeds, Seal are smaller, furrier, and have stubbier front feet. Sea lions, on the other hand (or flipper, are bigger and noisier, with elongated front flippers. Sea lions also tend to be much more social, sometimes congregating in groups of over a thousand individuals, while seals are comparative loners and spend more time in the water (the only time you're likely to find a group of seals together is when it's time to mate). Sea lions are capable of "walking" on dry land by rotating their hind flippers and are more vocal than seals.
Are you more confused now than you were before? I hope not! I do hope that after reading this blog, you're better able to distinguish the differences between all these wonderful creatures. Please come back tomorrow when I'll have a few valuable lessons from, of all people, William Shakespeare! Until then, have a great week and I wish you