Why Pair plot is taking up the target variable into consideration? I am working on Haberman's cancer survival data set.

I tried to visualize the pair plot with features as AGE, Op_Year, axil_nodes_det and target variable as Surv_status. I expect 12 plots but getting 16 including plots with Surv_stautus which is my target variable
here is my code: 

sns.set_style("whitegrid");
sns.pairplot(patients, hue="Surv_status", size=3);
maybe because Surv_status is number.
there are two solution:


define variables:

sns.set_style("whitegrid"); sns.pairplot(patients, hue="Surv_status",vars=["AGE", "Op_Year", "axil_nodes_det"], size=3);

change target value to a string:

patients['Surv_status'] = patients['Surv_status'].astype(str)



or 

    patients['Surv_status'] = patients['Surv_status'].str