My second favorite would have to be the Guinea Pig - not quite as social with people as rats (at least mine wasn't) but more so than most hamsters or mice.
1	My	my	PRON	PRP$	Case=Gen|Number=Sing|Person=1|Poss=Yes|PronType=Prs	3	nmod:poss	3:nmod:poss	_
2	second	second	ADJ	JJ	Degree=Pos|NumType=Ord	3	amod	3:amod	_
3	favorite	favorite	NOUN	NN	Number=Sing	5	nsubj	5:nsubj|10:nsubj:xsubj	_
4	would	would	AUX	MD	VerbForm=Fin	5	aux	5:aux	_
5	have	have	VERB	VB	VerbForm=Inf	0	root	0:root	_
6	to	to	PART	TO	_	10	mark	10:mark	_
7	be	be	AUX	VB	VerbForm=Inf	10	cop	10:cop	_
8	the	the	DET	DT	Definite=Def|PronType=Art	10	det	10:det	_
9	Guinea	guinea	NOUN	NN	Number=Sing	10	compound	10:compound	_
10	Pig	pig	NOUN	NN	Number=Sing	5	xcomp	5:xcomp	_
11	-	-	PUNCT	:	_	10	punct	10:punct	_
12	not	not	PART	RB	_	13	advmod	13:advmod	_
13	quite	quite	ADV	RB	_	14	advmod	14:advmod	_
14	as	as	ADV	RB	_	15	advmod	15:advmod	_
15	social	social	ADJ	JJ	Degree=Pos	10	parataxis	10:parataxis	_
16	with	with	ADP	IN	_	17	case	17:case	_
17	people	people	NOUN	NNS	Number=Plur	15	obl	15:obl:with	_
18	as	as	ADP	IN	_	19	case	19:case	_
19	rats	rat	NOUN	NNS	Number=Plur	15	obl	15:obl:as	_
20	(	(	PUNCT	-LRB-	_	24	punct	24:punct	SpaceAfter=No
21	at	at	ADP	IN	ExtPos=ADV	24	advmod	24:advmod	_
22	least	least	ADJ	JJS	Degree=Sup	21	fixed	21:fixed	_
23	mine	my	PRON	PRP	Number=Sing|Person=1|Poss=Yes|PronType=Prs	24	nsubj	24:nsubj	_
24-25	wasn't	_	_	_	_	_	_	_	SpaceAfter=No
24	was	be	AUX	VBD	Mood=Ind|Number=Sing|Person=3|Tense=Past|VerbForm=Fin	15	parataxis	15:parataxis	_
25	n't	not	PART	RB	_	24	advmod	24:advmod	_
26	)	)	PUNCT	-RRB-	_	24	punct	24:punct	_
27	but	but	CCONJ	CC	_	29	cc	29:cc	_
28	more	more	ADV	RBR	Degree=Cmp	29	advmod	29:advmod	_
29	so	so	ADV	RB	_	15	conj	15:conj:but	_
30	than	than	ADP	IN	_	32	case	32:case	_
31	most	most	ADJ	JJS	Degree=Sup	32	amod	32:amod	_
32	hamsters	hamster	NOUN	NNS	Number=Plur	29	obl	29:obl:than	_
33	or	or	CCONJ	CC	_	34	cc	34:cc	_
34	mice	mouse	NOUN	NNS	Number=Plur	32	conj	29:obl:than|32:conj:or	SpaceAfter=No
35	.	.	PUNCT	.	_	5	punct	5:punct	_
