Are there advantages in having a long neck in the animal kingdom?
Having long necks helps giraffes, camels, and llamas reach leaves and branches in tall trees that smaller herbivorous mammals cannot reach.
Almost all mammals have seven cervical vertebrae (bones) in their necks, whether they have long necks or short necks. Humans have seven neck bones too.

Rothschild’s Giraffe

Camel
Ostriches, emus, and cassowaries are ground birds that cannot fly, so having long necks helps them see predators from a distance. They can run away quickly from danger, instead of flying away.
These ratites (flightless birds) live predominantly in dry regions with limited water. Their necks are very flexible so they can clean and preen their feathers without the need for a water hole. Smaller, nimble birds splash around in water to help them clean their feathers.
Herons, storks, flamingos, cranes, geese and some egrets have long necks. They are aquatic birds (water or wetland birds) that wade in shallow water. They use their strong beaks to catch fish. Having a long flexible neck means that they can strike quickly.

Great Egret
Birds usually have more cervical vertebra than mammals. Most birds have highly flexible necks consisting of 13-25 cervical vertebrae.
Long-necked animals have adapted to feeding and surviving in their regional habitat.

White Swan

Humans have 7 cervical vertebra – Anatomography, 20 October 2012, https://en.wikipedia.org/wiki/Cervical_vertebrae#/media/ File:Cervical_vertebrae_lateral2.png
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM