Which detail should Mateo take out of his essay about unique animals? A shrimp's heart is located in its head. Elephants are the only animals that cannot jump. Koalas have fingerprints similar to humans. All mammals give birth to live young.

The detail about all mammals giving birth to live young should be taken out of Mateo's essay about unique animals.

From the details provided, Mateo should take out the fact that all mammals give birth to live young.

To determine which detail Mateo should take out of his essay about unique animals, let's go through each option and consider its accuracy and relevance.

1. "A shrimp's heart is located in its head."
This is an interesting and uncommon fact about shrimp anatomy. It adds to the uniqueness of these creatures and can engage readers. It provides valuable information and should be kept in the essay.

2. "Elephants are the only animals that cannot jump."
This fact highlights a distinct physical limitation of elephants. It helps create a clear picture of their unique capabilities and behavior. It is relevant to the topic and should be kept in the essay.

3. "Koalas have fingerprints similar to humans."
This detail demonstrates a fascinating similarity between koalas and humans. It showcases the different aspects of their biology and can captivate readers. It is an interesting observation and deserves to stay in the essay.

4. "All mammals give birth to live young."
While this statement is technically true, it is a common knowledge fact rather than a unique trait. It does not add any additional insight or intrigue to the essay on unique animals. Given that the other options are more distinctive, this detail should be removed from the essay.

In summary, the detail that Mateo should take out of his essay about unique animals is "All mammals give birth to live young."