Read this sentence. The tracking Party follow their prey to the river, but they're very lost the trail, Even though they had several bloodhounds with them. What type of sentence is this?

That sounds like it would be a a compound-complex sentence and hete's why.

A compound-complex sentence is made at least of 2 independent clauses and at least one dependent one. The independent clauses here are "The tracking party followed their prey to the river" and "there they lost the trail", while the dependent clause (which always start with subordinating conjunctions) is even though they had several bloodhounds with them.