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. 2011 Mar 8;6(3):e14753. doi: 10.1371/journal.pone.0014753

Figure 3. Labeling of observed behavioral sequences by HMM.

Figure 3

The HMM formalism takes into account both the frequency and order of a series of observed behaviors to identify and label behavioral states. Examples of HMM state labeling for representative sequences of maternal behavior take from two C57BL/6 mothers (60 observations per hour). Note how bouts of nursing (A and N states) typically start and end with licking and grooming of pups (L). Also, while nursing states (A, N, L) generally last for over ten minutes, activity states (C and E) are much more brief. Observed behaviors: N = blanket nursing, R = rearing, M = moving pups, G = self-grooming in nest, Z = digging, W = sniffing nest, E = eating, D = drinking, A = arched-back nursing, U = sniffing pups, P = licking/grooming pups, S = sniffing cage, B = nest building, and V = self-grooming out of nest; HMM states: C = activity, E = eating, L = grooming pups, G = self-grooming, A = arched-back nursing, N = blanket nursing.