if you are including los to treat cats as a subject, instead of an object, it's not correct in this sentence. Since it says "these" it is referring to a specific group of cats which can only be an object, not a subject. Or like rspreng said, you are adding "the" but i am not sure for what reason since the sentence doesnt require it.
esta/este/esto = this (fem/masc/unknown)
estas/estos = these (fem/masc)
esa/ese/eso = that (fem/masc/unknown)
esas/esos = those (fem/masc)
There is no neuter form in plurals. Note that masculine singular ends in E not O
And an easy way to remember it is "T is for Me, This and These" because the words for this and these are the ones with the T's in them.
What is the difference between the English and the Spanish demonstratives?
In English we used:
• “this” to talk about what is near the speaker.
• “that” to talk about what is far from the speaker.
But in Spanish we have three “semantic fields”, three differences:
• “este” to talk about what is near the speaker.
• “ese” to talk about what is near the listener.
• “aquel” to talk about what is far from both, speaker and listener.
By the way, it is the same difference about "here and there" and "aqui, ahí and allí or allá"
To jasonrech, as per Google:
Demonstrative adjectives are special adjectives or determiners used to identify or express the relative position of a noun in time or space. A demonstrative adjective comes before all other adjectives in the noun phrase. Some common demonstrative adjectives are this, that, these, and those.
Demonstrative pronouns. Pronouns that point to specific things: this, that, these, and those, as in “This is an apple,” “Those are boys,” or “Take these to the clerk.” The same words are used as demonstrative adjectives when they modify nouns or pronouns: “this apple,” “those boys.”
CattleRustler, "los" is used before Spanish nouns in order to indicate that the noun is being spoken of "in general." It doesn't matter where in the sentence the Spanish noun appears. It can be anywhere that a Spanish noun can be placed, such as where subjects go or where objects go.
For example, "Los perros y los gatos nos odiamos" = "Dogs and cats hate each other." You could equally write, "Los perros se odian los gatos," which gets translated as "Dogs hate cats."
I wrote this in response to several comments on this page. There are so many facets to this comment that I chose to place it on a higher level.
"Los" can be used before any noun to speak of "something in general," as in "Me gustan los gatos," (I like cats). Anywhere—not just as a sentence's subject—that a noun or noun substitute can be used, that noun can be spoken of "in general." The decision of whether to speak of "cats in general," as opposed to "specific cats," rests with the person speaking or writing. Obviously, a sentence like "Estos son gatos" is indicating that "estos" is a subset of "gatos."
So, when someone says/writes "Estos son gatos," the object "gatos" also can take the article in order to generalize because the reference is either to specific cats or to cats in general. As always, context—and by this I mean additional words—determines which. For instance, if I were referring to lions I might say "Estos son los gatos," meaning that they epitomize everything I like about cats. It's a general statement, but it's also specific to one complete set of felines (all lions in general). Conversely, if I were referring to how domesticated cats always leave mice lying around as a present for their owners, I might say, "Estos son los gatos," meaning this is a typical behavior of cats.
Leaving out Spanish articles, be they definite or indefinite, signifies that the exact number of the noun is unknown. When the definite article (los/las) is omitted, the nouns in that set are either infinite or a 100% complete subset. When the indefinite article is omitted, the nouns in that set are the opposite: a percentage of the whole or an incomplete subset. That is why it is optional to say "Quiero las galletas" (I want the cookies) or "Quiero galletas" (I want [some] cookies). In the first sentence, I am speaking of a finite set of cookies. In the second sentence, I can't possibly eat all the cookies in the world, so it can be inferred that the lack of an article means that I want some, but not all, of 100% of the cookies, be they the infinite set or the infinite subset.