Biologists think that fear causes this "hypnosis," which may be an attempt to "play dead" to fool predators.
1	Biologists	biologist	NOUN	NNS	Number=Plur	2	nsubj	2:nsubj	Discourse=attribution-positive:9->10:1|Entity=(10-person-new-cf2-1-sgl)
2	think	think	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	0:root	_
3	that	that	SCONJ	IN	_	5	mark	5:mark	Discourse=context-background:10->5:3
4	fear	fear	NOUN	NN	Number=Sing	5	nsubj	5:nsubj	Entity=(11-abstract-new-cf3-1-sgl)
5	causes	cause	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	2	ccomp	2:ccomp	_
6	this	this	DET	DT	Number=Sing|PronType=Dem	8	det	8:det	Entity=(8-event-giv:act-cf1*-3-coref
7	"	''	PUNCT	``	_	8	punct	8:punct	SpaceAfter=No
8	hypnosis	hypnosis	NOUN	NN	Number=Sing	5	obj	5:obj|15:nsubj	SpaceAfter=No
9	,	,	PUNCT	,	_	8	punct	8:punct	SpaceAfter=No
10	"	''	PUNCT	''	_	8	punct	8:punct	_
11	which	which	PRON	WDT	PronType=Rel	15	nsubj	8:ref	Discourse=elaboration-attribute:11->10:0
12	may	may	AUX	MD	VerbForm=Fin	15	aux	15:aux	_
13	be	be	AUX	VB	VerbForm=Inf	15	cop	15:cop	_
14	an	a	DET	DT	Definite=Ind|PronType=Art	15	det	15:det	Entity=(12-event-new-cf5-2-sgl
15	attempt	attempt	NOUN	NN	Number=Sing	8	acl:relcl	8:acl:relcl	_
16	to	to	PART	TO	_	18	mark	18:mark	_
17	"	''	PUNCT	``	_	18	punct	18:punct	SpaceAfter=No|XML=<q>
18	play	play	VERB	VB	VerbForm=Inf	15	acl	15:acl:to	_
19	dead	dead	ADJ	JJ	Degree=Pos	18	xcomp	18:xcomp	SpaceAfter=No
20	"	''	PUNCT	''	_	18	punct	18:punct	Entity=12)|XML=</q>
21	to	to	PART	TO	_	22	mark	22:mark	Discourse=purpose-goal:12->11:0
22	fool	fool	VERB	VB	VerbForm=Inf	18	advcl	18:advcl:to	_
23	predators	predator	NOUN	NNS	Number=Plur	22	obj	22:obj	Entity=(13-animal-new-cf4-1-sgl)8)|SpaceAfter=No
24	.	.	PUNCT	.	_	2	punct	2:punct	_
