Post-surgery radiographs of California sea lions with implanted life history transmitters. (A) Dorsoventral view of single transmitter in animal CSL6018, a 66 kg female – the tag has a size of approximately three vertebrae. (B) Lateral view of single transmitter in CSL6018. (C) Dorsoventral view of dual transmitters in animal CSL6053, a 195 kg male. The tags have a size of approximately two vertebrae.