Whether a cockroach is truly an animal is a common question. The definitive answer, according to biological classification, is yes. Understanding why requires examining the foundational rules of taxonomy, the system scientists use to organize all life on Earth. This process places the cockroach firmly within the largest grouping for all animals, the Kingdom Animalia.
Yes, A Cockroach Is Classified as an Animal
The term “animal” in a biological context is much broader than its everyday usage. A cockroach, along with an earthworm, a jellyfish, and a human, is formally classified under the Kingdom Animalia. This highest-level grouping includes organisms that share fundamental characteristics distinguishing them from plants, fungi, and single-celled life forms. The sheer diversity of Animalia means that millions of species, including the approximately 4,600 known species of cockroach, belong to this single kingdom.
Essential Characteristics of the Animal Kingdom
Membership in the Animal Kingdom requires meeting several biological criteria.
- All animals are multicellular, meaning their bodies are made up of numerous specialized cells working together. This distinguishes them from single-celled organisms.
- Animal cells are eukaryotic and lack rigid cell walls, which is a significant difference from plants and fungi.
- Animals are heterotrophs, meaning they must consume other organisms for energy rather than producing their own food.
- Most species are motile at least during some stage of their life cycle. A cockroach demonstrates this mobility throughout its life.
The Cockroach’s Place in the Biological Hierarchy
Below the Animal Kingdom, the cockroach is placed into more specific groups that describe its unique physical form and evolutionary path. It belongs to the Phylum Arthropoda, which is the largest animal phylum and includes all insects, spiders, and crustaceans. Arthropods are characterized by having a segmented body, a hard external skeleton called an exoskeleton, and jointed appendages.
The cockroach’s body is clearly segmented, divided into a head, thorax, and abdomen, and its stiff, chitinous shell acts as its armor and support structure. Moving down the classification ladder, the cockroach is further grouped into the Class Insecta. Insects are a specialized subset of arthropods defined by having three distinct body segments and precisely three pairs of legs, totaling six. This anatomical arrangement, from its segmented structure to its six jointed legs, confirms the cockroach’s position as an insect and, therefore, undeniably an animal.