Many animals have streamlined body shapes and hollow bones, for the simple reason they strive to go faster, either in a water environment or in the air (Aerodynamics).
Birds have hollow bones and usually have streamlined bodies if they are the product of natural evolution, unlike many game birds today.
In the water, many of the more aquatic mammals, such as Otters, are streamlined to go faster underwater. They do not, however, have hollow bones, their weight supported by the water, as is the case with many of the mammals. Seals and such do not have hollow bones, although they have a layer of blubber and smooth skin, and a mainly streamlined body.
Many birds have hollow bones to make it easier for them to fly
Understand that a streamlined body shape achieves a greater speed. A streamlined body shape is one that is narrow at both ends, and broad in the middle. This shape enables the animals to fly faster. Streamlined body shape Just like there is water resistance, there is a force called air resistance that opposes motion in air. When a bird is flying, its streamlined body shape helps to reduce air resistance
It has hollow bones to let it be lighter, streamlined body shape to reduce air resistance and strong muscles to flap their wings.
I think turtle and octopus
BONES
This is because the duck has the shape as a boat that helps it to swim and it does not have hollow bones. A pigeon can fly because it has hollow bones to make it light and its body is like a ship
An octopus is capable to streamlining its body when on the move. A squid, on the other hand, is usually always in a streamlined shape on account of having bones.
They have a Streamline shape, wings ,feathers and hollow bones.
No. Some animals( example. Puffer fish) don't depend on speed so they don't have streamlined body shape. Other fish that depends on speed to catch fish or running away from predator have streamlined body shape so that they can swim faster.
Their shape and aerodynamic efficiency makes them streamlined.
streamlined shape
Sharks, Tuna, Mackerels, and Marlins are all examples of Streamlined body shape fishes.
A tuna and other fishes have a thunniform body plan which is streamlined to minimize drag within the water.