"Whales" are a boogeyman to explain irrational trading, and justify why you are sitting on huge loses (or substantial gains).  In regular markets, whales certainly exist, they control large fund that they can move market... a few % here or there, enough to make them and friends substantial profits through leveraged positions.  In currency market for example, you might have a trader controlling $1bn, he only needs to move the market 0.1% in his favour and make a $1m profit for the day, trebles all round.

In crypto im not convinced they are the same creature, the financial instruments aren't available.  A whale may buy up a crypto but trying to sell down the market to buy back is risky, they have to first accumulate a position then sell it to then buy back.  What if it stays low?  On the other hand the volumes and amounts needed to shit the market are relatively small.

Though really most the large movements are simply irrational, lacking real fundamentals to anchor value, the technical analysis and day trading dominate sentiment.