Generally, yes. Try some examples to see. I've done a lot of comparisons of game world simulators written in Go and Scala, accomplishing similar things with radically different memory footprints. I think the difference has to do with the fact that everything you do in Scala produces tons of little objects for anonymous functions and loop iterators and so on.

For many applications this doesn't matter, especially with how cheap RAM is. But for some applications, such as mobile games and rented server space where your profitability is a function involving RAM cost per user, this can be very significant.

This is absolutely true if you are writing idiomatic Scala code (especially if you are using their collections api).

That said, you can lower your memory requirements dramatically using pretty standard high performance JVM techniques in Scala much as you can in Java. I've designed server systems in scala that produce no garbage for weeks at a time.

This can be a good option if you have some small subset of your system that needs to be memory sensitive/high performance without having to lose the benefits of the JVM in the rest of the system.