Smallest Vertebrates

This pygmy shrew is North America’s smallest mammal (this specimen is about 1.7 inches long), but the Eutruscan shrew is a bit smaller.

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While packing for an upcoming trip to Ecuador, I considered whether or not to take my 10X handlens. I wondered just exactly what kinds of small critters I might find where the viewing of which would be enhanced by the powerful lens. I did a little research and found that I might find a lot of insects, but i wasn’t likely to see any of the world’s smallest vertebrates. The subject was interesting, though and I thought I would share it.

There is always a smallest version of an animal. For instance, the Borneo pygmy elephant is a full five feet shorter than the African elephant. However, it is still large at eight feet tall. Dwarf sperm whales are the smallest of the whales at only nine feet long and up to 600 pounds, far smaller than a newborn blue whale (23 feet long and 5,500 pounds). However, these aren’t truly tiny and would not require a handlens to seriously study them.

Each class of animal is going to have a champion of small. Although great white sharks can reach 20 feet, the dwarf lantern shark reaches only eight inches, not even a snack for a great white shark. Within our own order, the Madame Berthe’s mouse lemur of Madagascar holds the record of the world’s smallest primate. It has a body length of just five inches and weighs 1.2 ounces.

So, what are the smallest vertebrates in the world? In the mammalian realm, the decision comes down to whether you are talking about length or weight. The Etruscan shrew weighs 1.5 grams, about as much as a raisin and is 1.2-2 inches excluding tail. However, the bumblebee bat of Thailand is shorter than the shrew at 1.14–1.30 inches, but weighs 1.7-2.0 grams. Which is the smallest?

Try to imagine the world’s smallest bird. This resident of Cuba is only two inches long with a wingspan of one and a quarter inches. This bird is so small it is named after an insect—the bee hummingbird.

If you are afraid of snakes, there is one snake you will never need to fear because you won’t likely see it—the Barbados threadsnake. This diminutive creature is typically less than four inches long and the diameter of a spaghetti noodle. This critter is found on the Caribbean islands of Barbados and Anguilla.

There are a lot of small fish, we often collectively and mistakenly call them minnows or guppies, but there is one, an angler fish known as Photocorynus spiniceps, that sets the record for the smallest fish and vies for the position of the smallest vertebrate. While the female may be two inches long, the male, which spends most of its life as a parasite on the female (okay, ladies, no comparisons here) and is not much longer than a quarter of an inch. As ocean dwellers though, they are hard to find.

Amphibian and reptiles are where a handlens might be useful. Among the reptiles, the dwarf gecko is considered the smallest reptile. However, there are 82 species of dwarf gecko, so the record for the smallest of the small goes to a Dominican Republic native, the Jaragua dwarf gecko. This lizard is 0.62 inches long and could rest comfortably on the tip of my little finger.

The winner of the smallest vertebrate contest, if it isn’t the angler fish, is a relative newcomer on the animal scene. The Brazilian flea toad (actually a frog, not a toad) was discovered in 2011. Researchers set out to find out if this frog, which could set up house on a dime and is the size of a house fly, was smaller on average than the then current record holder, a frog (Paedophryne amanuensis) from New Guinea. After lots of measurements, it was determined that the average male flea toad was 7.1 mm long while the male of the New Guinea species averaged 7.7 mm long. Hence, a new world record for the smallest vertebrate, and one where a handlens would be useful. Too bad they don’t live in Ecuador (at least that we know of).

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Help Idaho Wildlife

When we traveled across the state in October 2017, most of the vehicles we saw using the wildlife management areas did not have wildlife plates. Buying wildlife plates is a great way for non-hunters and hunters alike to support wildlife-based recreation like birding.

C'mon folks, let's help Idaho's wildlife by proudly buying and displaying a wildlife license plate on each of our vehicles! 

See below for information on Idaho plates. Most states have wildlife plates so if you live outside Idaho, check with your state's wildlife department or vehicle licensing division for availability of state wildlife plates where you live. 

And tell them that you heard about it from Nature-track.com!

Wildlife License Plates

Great news! as of 2024, there are three NEW designs for license plates. They still are bluebird, cutthroat trout and elk, but they are beautiful.

Idaho Wildlife license plates provide essential funding that benefits the great diversity of native plants and wildlife that are not hunted, fished or trapped—over 10,000 species or 98% of Idaho’s species diversity. Game species that share the same habitats (such as elk, deer, antelope, sage-grouse, salmon, trout) also benefit from these specialty plates.

No state tax dollars are provided for wildlife diversity, conservation education and recreation programs. Neither are any revenues from the sale of hunting or fishing licenses spent on nongame species. Instead, these species depend on direct donations, federal grants, fundraising initiatives—and the Idaho Wildlife license plates.

Both my vehicles have Bluebird Plates. I prefer the bluebird because the nongame program gets 70 percent of the money from bluebird plates, but only 60 percent of the money from elk and trout plates - 10 percent of the money from elk plates supports wildlife disease monitoring and testing programs (to benefit the livestock industry) and 10 percent from cutthroat plates supports non-motorized boat access.

Incidentally, in 2014, the Idaho Legislature denied the Department of Fish and Game the ability to add new plates or even to change the name of the elk and cutthroat plates (very specific) to wildlife and fish plates, a move that would have allowed for changing images occasionally and generating more revenue. It would seem that they believe that we Idahoans don't want a well funded wildlife program.

I think it is time we let the Legislature know that Idahoan support wildlife funding and that we would like to see these generic plates come to fruition.