Top 10 Slowest Animals In North America


The animals of North America include some of the most diverse species in the world. They are of all different sizes, shapes, colors, and speeds. 

You may have read my other article on the fastest mammals in North America, but what about the slowest? 

Here is a list of the ten slowest animals in North America, starting at the fast, slow end and working down to some of the slowest creatures on the continent, and perhaps maybe in the world.

10. Swallowtail Butterfly

Swallowtail butterfly

Swallowtail butterflies are actually a group of insects that belong to the family Papilionidae. This family is comprised of about 560 butterfly species, with different species living all over North America. Their name derives from their appearance, especially the pointed tips of their hind wings, which resemble that of the swallow bird.

Swallowtail butterflies can be brightly-colored or have darker wings with light spots. Their natural appearance can mimic that of poisonous species, for protection.

Their wing-beat speed — the slowest of all insects — makes them one of the slowest animals in North America. This allows the swallowtail to feed on its most common foods, which in the case of the Eastern Tiger Swallowtail (Papilio glaucus) include lilac, wild cherry, and milkweed nectars.

Compared to that of a midge fly (several species of the order Diptera), which is 62,760 beats per minute, the swallowtail butterfly’s wings flap at only 300 beats per minute.   

9. Manatees

Manatee

The manatee is one of the slowest-moving mammals of the North American continent. The Florida Manatee (Trichechus manatus latirostris) is a subspecies of the West Indian Manatee (Trichechus manatus) and inhabits coastal areas along with Florida, the Gulf Coast, and the Eastern Seaboard, up to Massachusetts.

These animals can grow from eight to thirteen feet in length and weigh as much as 1,300 pounds. Historically, the manatee likes to inhabit warm waters, generally being attracted to warm natural springs.

Currently, however, the manatee is attracted to warm-water outflow from power plants and other human-made sources. Unlike other animals, manatees have lungs along their backs, which expand and contract to give them varying degrees of buoyancy.

Though they can swim in short bursts up to 15 miles an hour, this elephant relative generally swims at slower rates. Grazing on seagrass and other marine plants, manatees gently float at 4.8 to 8 km/hr (3 to 5 miles per hour).

8. Rosy Boas

Rosy Boa

The Rosy Boa (Lichanura trivirgata) is a snake species that is one of the two native boas of the United States. Dwelling in the American Southwest and the states of Sonora and Baja, Mexico, these snakes are used to staying out of the sun under rocks and in burrows.

They are usually seventeen to forty-four inches long and have a round, smooth body that is in varying shades of brown, orange, gray, and even blue.

Feeding on small birds, snakes, lizards, amphibians, and rodents, the Rosy Boa kills by constricting its prey. That said, it can strike quickly — but its normal crawling speed is about 1.6 km/hr (1 mile per hour) — making it one of the slowest snakes in the world.

7. Gila Monsters

Gila monster

The Gila Monster (Heloderma suspectum) is another reptile that lives in the American Southwest and the Sonoran Desert — though it is also capable of living in the mountains, at elevations up to five thousand feet.

This roughly two-foot-long lizard weighs in at about four pounds and has a distinctive black-and-orange (or yellow, or pink) pattern. Though it favors the rocky outcroppings of desert foothills, it spends a large amount of time underground.

It only comes to the surface to sun itself, albeit rarely. A venomous lizard (though not harmful to humans), the Gila Monster feeds on bird eggs and small newborn mammals.

It has very low metabolism and this results in the reptile’s large size. A Gila Monster indeed can consume the number of calories it needs for a year in three or four large meals. Still, it manages a pace of 1.6 km/hr (1 mile per hour) matching that of the Rosy Boa.

6. Starfish

Starfish

Starfish belong to a large genus called Asteroidea, which contains over 1,500 starfish species worldwide. In North America, starfish inhabit both coasts — from the Northwest Pacific-dwelling Pink Sea Star (Pisaster brevispinus) to the Atlantic’s Common Sea Star (Asterias rubens).

Typically, starfish live in rocky shallows or gravel-laden parts of deeper waters. They are normally carnivorous and tend to eat stationary bivalves — like oysters, clams, and mussels — with some species extending their stomach far beyond their mouth.

As many species do not need to travel quickly to feed or mate (males and females typically release spores into the water), starfish have evolved to be very slow creatures, often traveling at speeds of 0.096 km per hour (0.06 miles per hour).

5. Desert Tortoises

Desert Tortoise

Desert tortoises are a couple of species of reptiles that are common in the Mojave and Sonoran deserts (Southern California, Nevada, Utah, Arizona, and Northwestern Mexico). They grow to about nine to fifteen inches in length and can weigh as much as fifteen pounds.

Desert tortoises are actually two species, Gopherus agassizii and Gopherus morafkai — living west and east of the Colorado River, respectively. They have a hard, high shell that is domed in shape and can withdraw their limbs completely underneath it.

Feeding on cacti, grasses, and wildflowers, desert tortoises do not need to move fast to capture prey or run away from predators. Often burrowing underground for cover, these animals have a walking speed of only 0.05 km/hr (0.03 miles per hour).

4. Garden Snails

Garden snail

Whether you consider it to be a garden pest or a delightful delicacy, the garden snail (Cornu aspersum) is one of North America’s slowest gastropods. Existing on the continent entirely as an introduced species, this species inhabits Canada, Mexico, Haiti, Martinique, and large parts of the United States.

Garden snails have a distinct shell that is 1.1 to 1.7 inches in diameter and typically feeds on flowers, plants, and shrubs; they also particularly favor citrus plants and fruit.

Their bodies are lined with mucus to trap moisture in, and though their shells provide some protection, they are often prey to insects, lizards, amphibians, and birds. They travel at a rate of 0.047 km/hr (0.029 miles per hour) on average.

3. Banana Slugs

Banana slug

The banana slugs are actually several species that belong to the genus Ariolimax. These gastropods can grow up to 9.8 inches and are usually yellow in color, though they can be white, tan, or greenish.

They live on the damp forest floors of the Pacific Northwest (from Alaska down to Northern California) and feed on dead organic matter, moss, fallen plants, and animal feces. With bodies comprised mostly of water, these slugs secrete mucus to keep in moisture.

The mucus also has the added benefit of being bad-tasting to predators. As members of Ariolimax only have one lung and one foot, their speed is very limited — clocking in at 0.0098 km/hour (0.0061 miles per hour).

2. The Dwarf Seahorse

Dwarf seahorse
Dwarf seahorse

The Dwarf Seahorse (Hippocampus zosterae) is considered to be the slowest fish in existence (by the way, starfish are not actually fish). They are also one of the world’s smallest seahorses, at about 1 inch in length.

This species inhabits grassy seabeds of the Gulf Coast, the Caribbean, and the eastern coast of Florida. They swim by propelling themselves with their dorsal fins and steering with their pectoral fins. This results in an upright mobile position — one that is used to eat copepods, small shrimp, and very tiny fish.

Mating behaviors are like many seahorse species, in which fertilized eggs are kept inside the male’s pouch, to brood for a period of 11 days. The Dwarf Seahorse lives among floating vegetation and can afford to travel at very slow speeds — about 0.0015 km/hour (.00093 miles per hour).

1. Sea Anemones

Sea anenome

Sea anemones are animals that belong to the scientific order Actiniaria. They are closely related to jellyfish, corals, and water-dwelling animals known as a hydra.

Like many corals, sea anemones consist of polyps that attach to hard surfaces — and have tentacles and mouths with which they sting and consume their prey (usually, crabs, plankton, or tiny fish). They also have symbiotic relationships with green algae known as zooxanthellae in which the algae provide the anemone with glucose and amino acids, and the anemone provides carbon dioxide and other plant-sustaining nutrients.

There are over 1,000 species of sea anemones world-wide, with species like the Sunburst Anemone (Anthopleura sola) inhabiting the Pacific Northwest and the Giant Anemone (Condylactis gigantea) living in the Caribbean and off the Mexican and Floridian coasts.

Sea anemones can “glide” very slowly along their chosen surfaces, or detach from them completely to fasten onto other surfaces. They move at an astonishingly slow 1.016 e-6 km/hr (0.04 inches per hour) — that’s 0.000001016 km/hr (0.000000631 miles per hour) — making them the slowest animals on our list.

Bryan Harding

Bryan has spent his whole life around animals. While loving all animals, Bryan is especially fond of mammals and has studied and worked with them around the world. Not only does Bryan share his knowledge and experience with our readers, but he also serves as owner, editor, and publisher of North American Mammals.

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