Figure 1. Acquiring an annotated Hydra behavior dataset.

(a) Imaging Hydra behavior with a widefield dissecting microscope. A Hydra polyp was allowed to move freely in a Petri dish, which was placed on a dark surface under the microscope objective. The light source was placed laterally, creating an bright image of the Hydra polyp on a dark background. (b) Histogram of the eight annotated behavior types in all data sets. (c) Histogram of the duration of annotated behaviors. (d) Histogram of total number of different behavior types in 1 s, 5 s and 10 s time windows. (e–l) Representative images of silent (e), elongation (f), tentacle swaying (g), body swaying (h), bending (i), contraction (j), feeding (k), and somersaulting (l) behaviors.

Figure 1—figure supplement 1. Variability of human annotators.

(a) Two example segments of annotations from two different human annotators. (b) Confusion matrix of the two annotations from four representative behavior videos. The overall match is 52%.