I have data in an excel spreadsheet, I'm importing it using `XLConnect`.

One column has duration data that was recorded like this: m:ss 
R is displaying it as a strange date. 

Here's a sample of my data:

```
2:21
6:08
0:39
13:51

```

Here's a how R is interpreting it:

```
"1899-12-31 02:21:00"
"1899-12-31 06:08:00"
"1899-12-31 00:39:00"
"1899-12-31 13:51:00"

```

Any idea how I can get are to interpret it as duration of m:ss? 

EDIT: I want to compare, graph, and preform some mathematics on these times. Any idea