( ( ( social contact ) ( with ( ( other animals ) ( of ( their ( own kind ) ) ) ) ) ) ; )
(ROOT (NP (NP (JJ social) (NN contact)) (PP (IN with) (NP (NP (JJ other) (NNS animals)) (PP (IN of) (NP (PRP$ their) (JJ own) (NN kind))))) (: ;)))
social contact with other animals of their own kind;
(ROOT (S (PP (IN For) (NP (JJ social) (NNS animals))) (, ,) (NP (NN communication)) (VP (VBZ essential)) (. .)))