Cockroaches and lobsters are two groups in the same phylum.
"Beyond classification which should reflect the lobster and cockroach evolutionary relationship, the term 'roaches of the sea' reflects the behavior of lobsters as omnivorous scavengers. Cockroaches will eat almost anything organic and so will lobsters. They clean up the dead and dying plants and animals in their environment."Kosher laws make a lot of sense.
Joseph G. Kunkel, Professor, Biology Department, U. Massachusetts Amherst
These critters remind me a little of Republicans and Democrats. They seem different, but in the end they're both scavengers.