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!

1. Northern Water Snake

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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

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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

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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

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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

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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

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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

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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

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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

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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.
Number | Animal | Size | Range in Delaware |
---|---|---|---|
1 | Northern Water Snake | Can reach 4.5 feet long | Slow-moving water such as swamps, streams, and ponds |
2 | White-Tailed Deer | Can weigh up to 400 pounds; males are larger than females | Common across the state in a wide range of habitats, mostly in forests and pastures |
3 | Atlantic Bluefin Tuna | Length: 12 feet; Weight: 1,500 pounds | Appear on Delaware’s coast every year |
4 | Giant Water Bug | Can reach 4.5 inches long | Ponds, streams, and swamps statewide |
5 | Brown Pelican | Wingspan: 6 feet 8 inches to 7 feet 6 inches | Shallow saltwater habitats such as estuaries and along coastlines |
6 | Black Rat Snake | Can reach 8.5 feet long | Fairly common across Delaware in a variety of habitats including woodlands, prairies, and rocky outcrops |
7 | Bald Eagle | Wingspan can reach about 7 feet 7 inches | Large population overwinter in Delaware River Valley |
8 | Shortfin Mako Shark | Length: can reach 13 feet; Weight: 1,260 pounds | Sometimes occur near the Delaware coast |
9 | Fin Whale | Can reach almost 79 feet long | Lewes and Bethany Beach are the best places to spot them. |
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