Discover the 9 Largest Animals in Delaware, and Where You’ll Find Them

Written by Hannah Ward
Updated: July 29, 2023
© Paul Tessier/
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Delaware is the second smallest state in the United States but it is still filled with fascinating animals. The state makes up part of the Piedmont Plateau which encompasses many rolling hills and grasslands. Delaware also borders the Atlantic Ocean and has a vast range of marine animals which call it home, from whales and dolphins to seals and seabirds. But that’s not all the state has to offer, so read on to discover the largest animals in Delaware and where you’ll find them!

Infographic of 9 Largest Animals in Delaware
These are the biggest reptile, mammal, fish, insect, and bird species present in Delaware.

1. Northern Water Snake

Northern water snake
Northern water snakes can reach a length of 4.5 feet.


There are three types of water snakes found in Delaware and the most common is the northern water snake, which can reach 4.5 feet long. Northern water snakes are typically brown or brownish-black with darker crossbands and blotches on them. They have a similar appearance to the venomous cottonmouth snake, which often leads to them being killed out of fear. Northern water snakes inhabit slow-moving water in Delaware such as swamps, streams, and ponds where they hunt along the water’s edge. They prey mainly on small fish, frogs, lizards, and birds. Although they are not venomous they are capable of delivering a painful bite. Their saliva contains a mild coagulant that means any wounds they inflict tend to bleed a lot.

2. White-Tailed Deer

A white-tailed deer standing in a meadow
White-tailed deer can weigh up to 400 pounds.

©Paul Tessier/

Although most of Delaware’s largest mammals live in the sea, there are still some on the land, too. White-tailed deer are best known for their distinctive white patch on the underside of their tail. Males are larger than females and they can weigh up to 400 pounds. White-tailed deer are extremely adaptable animals and live in a wide range of habitats, although they most commonly live in forests and pastures. White-tailed deer are common right across Delaware and their population is estimated at 40,000+.

3. Atlantic Bluefin Tuna

Fastest Sea Animal: Atlantic Bluefin Tuna
The Atlantic bluefin tuna is one of the largest and fastest of all the world’s fishes.


One of the largest animals in Delaware is also one of the most powerful — the Atlantic bluefin tuna. These fish have torpedo-shaped bodies and are typically a dark blue on their upper side and a silvery grey on their underside. Atlantic bluefin tuna are capable of reaching 12 feet long and can weigh as much as 1,500 pounds. They are some of the most sought-after fish, both by commercial and sports fishermen. Bluefin tuna are some of the fastest fish around and can reach 50 miles per hour. Although bluefin tuna often inhabit deep, open water they regularly show up on Delaware’s coast every year.

4. Giant Water Bug

What Do Water Bugs Eat?
Giant water bugs live in ponds and streams in Delaware.


Delaware is also home to some pretty big bugs and some that you might prefer to avoid are giant water bugs, which are also known as “toe biters”. Giant water bugs are members of the Belostomatidae family group and the largest species can reach 4.5 inches long. They have dark brown to black bodies that appear as a flattened oval shape. Giant water bugs inhabit ponds, streams, and swamps right across the state. They are fierce predators and eat a range of insects, fish, snakes, and juvenile turtles. If they are picked up or disturbed then they can deliver an incredibly painful bite.

5. Brown Pelican

Brown Pelican in flight
Brown pelicans have a wingspan of more than 7 feet.

©Nagel Photography/

Although there are two types of pelicans that can be found in Delaware, the most common is the brown pelican, which can be found in shallow saltwater habitats such as estuaries and along coastlines. Brown pelicans have brown bodies with white heads and long bills. They have a huge wingspan, which ranges between 6 feet 8 inches and 7 feet 6 inches. Brown pelicans mainly feed on fish, although they do sometimes eat crustaceans, amphibians, and bird eggs. They have excellent eyesight and are able to spot schools of fish in the water below, even while flying 70 feet above the ocean. They then dive down to catch their prey. Brown pelicans live in flocks all year round and populations can be resident or migratory.

6. Black Rat Snake

An adult rat black snake peaks over a rock
The black rat snake is the largest snake in Delaware.

©Matt Jeppson/

The largest snake in Delaware is generally considered to be the black rat snake, which can reach 8.5 feet long. Black rat snakes have glossy black scales with white throats, chins, and lips. They are highly adaptable and live in a variety of habitats including woodlands, prairies, and rocky outcrops. They are fairly arboreal and tend to spend a lot of time in trees. During the winter they hibernate in dens with two types of venomous snakes: timber rattlesnakes and copperheads. Black rat snakes are not venomous and prey on small mammals, birds, and other snakes. Black rat snakes are fairly common across Delaware but can often be difficult to spot.

7. Bald Eagle

Bald Eagle flying over a lake.
Bald eagles have massive wingspans that can reach around 7 feet 7 inches.

©Jack Molan/

One of the best-known animals in Delaware is the stunning bald eagle, which has a distinctive appearance with its dark brown body and white head and tail. Bald eagles have a massive wingspan that can reach approximately 7 feet 7 inches. They are sea eagles and live near large areas of water such as lakes and coastlines. Fish make up the majority of their diet and they are scooped straight out of the water using their long, sharp talons. Bald eagles nest in trees near the water and have some of the largest nests known, which can be up to 9 feet wide and 20 feet deep. The Delaware River Valley is one of the best places to see these fascinating birds in Delaware as a large population of them overwinter there.

8. Shortfin Mako Shark

Short fin mako shark swimming just under the surface, about 50 kilometers off the Western Cape coast in South <a class=
Shortfin mako sharks can be up to 13 feet.


Some of the largest fish in Delaware are actually sharks and one of these is the shortfin mako shark, which can reach 13 feet long and weighs as much as 1,260 pounds. Shortfin mako sharks usually inhabit open waters at depths of up to 490 feet. However, they do sometimes occur near the Delaware coast and the largest caught in the state weighed 975 pounds. They are some of the fastest sharks around and can reach 43 mph in short bursts, usually when they are hunting. Shortfin mako sharks prey on a range of bony fish, sharks, sea turtles, and seabirds. They are an endangered species, in part because they are targeted by commercial fisheries.

9. Fin Whale

Fin Whale
Fin whales can be seen in Delaware.


The largest animal in Delaware is the massive fin whale, which can reach almost 79 feet long. Fin whales are baleen whales, which means they have huge baleen plates in their mouths rather than functional teeth that they filter their food through. Despite their huge size, fin whales actually have incredibly slender bodies that tend to give them the nickname “greyhound of the sea.” Fin whales are found in every major ocean around the world and Lewes and Bethany Beach are the best places to see them in Delaware. Fin whales were once almost hunted to extinction and although the population has recovered somewhat they are still classed as a vulnerable species.

Summary of the 9 Largest Animals in Delaware, and Where You’ll Find Them

Here’s a recap of the nine biggest animals found in Delaware that we took a look at.

NumberAnimalSizeRange in Delaware
1Northern Water SnakeCan reach 4.5 feet longSlow-moving water such as swamps, streams, and ponds
2White-Tailed DeerCan weigh up to 400 pounds; males are larger than femalesCommon across the state in a wide range of habitats, mostly in forests and pastures
3Atlantic Bluefin TunaLength: 12 feet; Weight: 1,500 poundsAppear on Delaware’s coast every year
4Giant Water BugCan reach 4.5 inches longPonds, streams, and swamps statewide
5Brown PelicanWingspan: 6 feet 8 inches to 7 feet 6 inchesShallow saltwater habitats such as estuaries and along coastlines
6Black Rat SnakeCan reach 8.5 feet longFairly common across Delaware in a variety of habitats including woodlands, prairies, and rocky outcrops
7Bald EagleWingspan can reach about 7 feet 7 inchesLarge population overwinter in Delaware River Valley
8Shortfin Mako SharkLength: can reach 13 feet; Weight: 1,260 poundsSometimes occur near the Delaware coast
9Fin WhaleCan reach almost 79 feet longLewes and Bethany Beach are the best places to spot them.

The Featured Image

A white-tailed deer standing in a meadow
A white-tailed deer standing in a meadow
© Paul Tessier/

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About the Author

I have been writing professionally for several years with a focus on animals and wildlife. I love spending time in the outdoors and when not writing I can be found on the farm surrounded by horses, dogs, sheep, and pigs.

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