Smallest animals around, for now!
The smallest creatures in a group are sometimes the most successful. As we see here, they can also be very vulnerable. We obviously agree that small is beautiful, and big can be bad. Large mass and volume can obviously be a strong factor encouraging survival in cold temperatures, or for storing fats. Whales and mammoths come to mind, but the advantages of small are also fairly obvious. Being able to get entry to the space created by others helps mammals, for example to hunt prey and even climb trees to obtain fruit leaves and flowers. Insects are restrained in size by their respiratory system, but being large means their predation is less likely, while small seems to be associated with the ability to produce huge populations. Such a knack has proved successful in bigger creatures, but the arthropods specialise in flooding the seas with krill and the forest with flies!
Among the smallest mammals are monkeys like the pygmy marmosets of the Amazon basin, Cebuella pygmaea. They are very un-monkey-like in some ways because they eat tree gum. They scrape and suck with very specialised teeth. They are beaten into umpteenth place among the mammals by the tiniest shrews, mole-shews, jerboas and possums and, finally the bumblebee bat, Craseonycteris thonglongya, which obviously gains because its lack of weight is a great aid in getting off the ground easily. It's another critically-endangered species, also known from its discoverer in Thailand as Kitti's hog-nosed bat.
The small whales are logically porpoises and dolphins, but as a toothed whale, the really reduced-size, dwarf sperm whale, Kogia breviceps stands out as the smallest, at 3.5m (11 feet), although we know almost nothing about it. In New Zealand the world's smallest dolphin, another critically-endangered species, Cephalorhynchus hectori mau still being trapped accidentally by fishermen. We wrote about its plight in the Maui dolphin story, noting that there are only about 50 adults left.
The reptiles and amphibian tend to compete as the world's smallest vertebrates with some tiny fish. The Papuan frog Paedophryne amanuensis at 7.7mm average length beats Paedocypris progenetica, the Indonesian cyprinid fish, simply because it has no tail! Both cheat on the competition by retaining larval form, so they are "neotenic," basically.
The little lizard, recently found on the forest floor, like many of the smallest frogs, is the Madagascan chameleon, Brookesia micra.It's easily the smallest reptile.We wrote about it here under a miniature chameleon discovered.
Invertebrates are so small that we might as well consider single cells. Then we would be faced with the giant Algae and the tiniest parasitic amoebae. Perhaps we have to stick with the smallest stingless bee, Trigona minima although another will be discovered tomorrow, no doubt. Most insects are supposed to be un-named yet, there are so many of them. The tiniest flies and even beetles can remain to be discovered!
I'll have to look at the biggest animals soon, I suppose, so roll on to the blue whale encyclopaedia entry.