The animals themselves are 3D rendered animations, requiring 3D animation software like Cinema 4D.
The light trails are created with a particle generator of some description. There's some partical generation built into After Effects (Particle Playground and CC Particle World) but both have limitations and complications.
The most popular Particle Generator for AE users is Trapcode Particular. Quite easy to use and very versatile, and has fluid dynamics like the particles in your example. But it'll cost you.
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