Homo Heidelbergensis:
Homo heidelbergensis is an extinct species of human that lived between 700,000 and 300,000 years ago during the Middle Pleistocene period. Here are some key characteristics and features of Homo heidelbergensis:

1. Cranial Capacity:
- Homo heidelbergensis had a larger cranial capacity compared to earlier hominin species, ranging from approximately 1,100 to 1,400 cubic centimeters.
- This suggests the species had a larger brain size and possibly enhanced cognitive abilities.

2. Physical Features:
- Homo heidelbergensis had a robust and muscular build, with an average height of around 5 feet 9 inches (175 cm) for males and slightly shorter for females.
- They had a prominent brow ridge, a projecting face, and a large nose.
- The species had large, sturdy teeth and a strong jaw.

3. Tool Use and Technology:
- Homo heidelbergensis was known to have used and created more advanced tools compared to earlier hominin species.
- They produced Acheulean handaxes, which were more refined and symmetrical compared to earlier tool types.

4. Hunting and Social Behavior:
- Homo heidelbergensis is believed to have been skilled hunters, capable of taking down large game.
- They likely lived in small social groups and may have had complex social structures.
- Evidence of intentional burial practices suggests a degree of symbolic behavior and possibly a belief in an afterlife.

Homo Neanderthalensis:
Homo neanderthalensis, commonly known as Neanderthals, lived between 400,000 and 40,000 years ago during the Middle to Late Pleistocene period. Here are some key characteristics and features of Homo neanderthalensis:

1. Cranial Capacity:
- Neanderthals had a similar or slightly larger cranial capacity compared to modern humans, ranging from approximately 1,200 to 1,700 cubic centimeters.
- This indicates that they had a comparable or slightly larger brain size.

2. Physical Features:
- Neanderthals had a robust and heavily muscled build, with an average height of around 5 feet 5 inches (165 cm) for males and slightly shorter for females.
- They had a distinctive skull shape, with a prominent brow ridge, a receding forehead, and a large nose.
- The species had a stocky build and shorter limbs compared to modern humans.

3. Tool Use and Technology:
- Neanderthals were skilled toolmakers and used a wide range of stone tools, including Mousterian tools.
- They used tools for hunting, but also for other tasks such as woodworking and preparing hides.

4. Hunting and Social Behavior:
- Neanderthals were excellent hunters and adapted to various environments, including cold and temperate regions.
- They lived in small family groups and likely had close-knit social structures.
- Evidence suggests that they cared for the injured and elderly, indicating a degree of compassion and social cooperation.

In summary, Homo heidelbergensis and Homo neanderthalensis share some similarities but also have distinct differences in cranial capacity, physical features, tool use, hunting abilities, and social behavior. These differences reflect the evolutionary changes and adaptations that occurred throughout the hominin lineage.

They both belong to the homo sapiens. The fossils of this are found in Europe at Heidelberg and Neanderthal in Germany. Their fossil names are derived from the places where the first fossils were found. ( since they both belong to the same category, I don't think there is much difference between them. )