  With the new era of genomics, an increasing number of animal species are
amenable to large-scale data generation. This had led to the emergence of new
multi-species ontologies to annotate and organize these data. While anatomy and
cell types are well covered by these efforts, information regarding development
and life stages is also critical in the annotation of animal data. Its lack can
hamper our ability to answer comparative biology questions and to interpret
functional results. We present here a collection of development and life stage
ontologies for 21 animal species, and their merge into a common multi-species
ontology. This work has allowed the integration and comparison of
transcriptomics data in 52 animal species.
