This pictures speaks for itself.

The Leatherback Sea Turtle is the largest turtle in the world, weighing approximately 900 kg. Contrary to appearance, the leatherback doesn't actually have a shell. What looks like a shell is in fact a leathery skin supported by small bones. This gives it a flexibility that a solid shell would not provide, allowing it to dive to astonishing depths.

This Malaysian katydid is one of the largest insects in the world, with their bodies growing to 15 cm (6 inches) long with a 25 cm (10 inch) long wingspan. Though the last thing you want to hear is that this giant insect is carnivorous, they pose absolutely no threat to humans (aside from haunting your dreams, of course).

Relatively speaking, the males of this species have the largest testes of any known animal at 14% of their body weight. If humans had the same ratio, a 91 kg (200 lb) man would have testes that weighed nearly 13 kgs (28 lbs)! ...

Aside from claiming the title of the largest animal known to have ever lived, the blue whale (Balaenoptera musculus) possesses a heart big enough to house a human. The heart of an average sized blue whale weighs 180 kg (400 lb) and is also the largest known in any animal.

During the first seven months of its life, a blue whale calf drinks approximately 380 litres (100 US gal) of milk every day. Blue whale calves gain weight quickly, as much as 90 kilograms (200 lb) every 24 hours. Even at birth, they weigh up to 2,700 kilograms (6,000 lb) - the same as a fully grown hippopotamus.

Blue whales have proportionally small brains, only about 6.92 kilograms (15.26 lb), about 0.007% of its body weight, although with a highly convoluted cerebral cor ...

The Mydas fly (Gauromydas heros) is the world's largest fly. It can reach body lengths of 2.8 inches (7 centimeters) and a wingspan of 4 inches (10 centimeters). Mydas fly are found in arid and semiarid regions of the world, but are infrequently encountered as the adult lifespan can be quite short.

This is the Giant weta. Native to the small islands of New Zealand, it's one of the heaviest insects in the world - the largest on record weighed around 70 g.