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Nervous Anatomy
Electric Organ
Organum electricum
Specialised muscle-derived tissue that generates electric fields - used for hunting, defence, navigation, and communication in over 500 fish species.
Region: Trunk Unique to: all
📖 Overview
Electric organs have evolved independently at least six times in fish. The electric eel (Electrophorus electricus) can deliver 860-volt shocks to stun prey - the highest known biological voltage. Torpedo rays paralyse fish with pulses; elephantfish generate weak fields for navigation and communication. All electric organs derive from modified muscle cells (electrocytes) stacked in series like batteries.
🧬 Structure
Columns of flat, disc-shaped electrocytes (modified muscle cells) stacked in series. Each cell generates roughly 150 millivolts; the total voltage depends on how many are stacked. Different arrangements produce different waveforms.
⚙️ Function
Strong-electric fish (Electrophorus, Torpedo): prey capture and defence. Weak-electric fish (Mormyridae, Gymnotidae): active electrolocation, communication with electric organ discharges (EODs).
🧭 Evolutionary Origin
Independent evolution in electric eels, catfish, marine rays, stargazers, and elephantfish - one of biologys most striking cases of convergent evolution.
🐠 Variations Across Species
Electric eel: 500+ volt output. Torpedo ray: 200 volts, high current. Elephantfish: weak communicating pulses at species-specific frequencies. Knifefish: continuous wave discharges.
✨ Fun Fact
An electric eel can jump partly out of the water to press its chin against a threatening predator - concentrating its shock through the animals nervous system rather than dispersing it into water.
🔗 Related Nervous Structures