In Polish one never forms plural with -s (or at least in 99,9% of cases). Most of the time we add or change vowel at the end.
There are even some eculiar examples of loanwords:
- jankes (jokingly or derogatory for an American), plural: jankesi (or jankesy which is a depreciative form) comes from Yankees (plural itself, singular Yankee)
- keks (plural: keksy) comes from cakes
- nuggets/nugets (plural: nuggetsy/nugetsy)
- baks (colloq. American Dollar) , plural: baksy, comes from: buck
- cornflakes/kornflejks, plural: cornlakesy/kornflejksy
Tygrys sounds like tigress. I saw it showed lion and lioness as lew. I wonder if animals are genderly dermined in polish.
In case of lions and tigers: tygrys (male), tygrysica (female), tygrysek, tygrysiątko, tygrysię (offspring, two first are diminutives)
lew (male), lwica (female), lwię and lwiątko (offspring, the latter is diminutive)
But also "lew" and "tygrys" are simply the names of the species. You usually can make a gendered version, but one is just the 'default'.