What the description of Sphacteria has to tell us

[Giannis K. Hoplite]

The Spartans in their charges were not aiming the Athenian line. The pursued the peltasts,obviously thinking that if they engaged the Athenian hoplites without routing the peltasts they would emediately be completely surrounded. The Athenians would have been on a higher ground in a great defensive position. The Spartans failed in their first task to defeat the lightly armed,not to reach the Athenian hoplites. This would have been their second task.
Of course what Kineas suggested is plausible. Thucydides has mentioned such cases where one of the oponents realize their disorder or casualties and retreat. Speaking about casualties,only in formation did the Athenians realize the amount of missing men after the naval battle of Arginousae and were panicked. I personally don't believe this is why the Spartans retreated. They actually charged and retreated many times,and Thucydides is clear when he says that not only they suffered casualties but were also utterly exausted. Retreat was a decission that should have been taken earlier...
Khairete
Giannis